I’m working on a crazy campaign with me and four friends. In it, each of our five characters need to obtain something to defeat the final boss, with each separate chapter dedicated to one player’s “trial” to get that item/ability/relic. But there’s a twist:
Each person will become the Dungeon Master to guide another player through their journey. This means all of us will be the DM for the first five chapters, leading up to the one-shot final boss.

So it’s a cool concept because it allows for each person to express some creativity, but I want there to be a real sensible storyline. Something that allows each of my friends to build their own crazy sections without hindering from the main storyline AND the relics/abilities they get actually help them defeat the final boss. Does that make sense?
Essentially, I need a final boss that’s big, and can only be fully defeated using five relics. I also need a story idea that makes sense, like each relic represents the five stages of grief and the boss represents loss.
Thats… a lot, but if you have any ideas that could help I’d really appreciate it 😅

The first thing that comes to mind is having a Lich or something that has 5 phylacteries, which can effectively serve as Horcruxes. You could also do something with finding keys to open a dragon's vault, though this is also a big cliche.

If you wanted to go the "5 stages of grief route", then here's what I would recommend: There was an ancient Cleric who used their powers for good, but their friend was abandoned and died in a war against evil and the Cleric was corrupted by it. They pretended nothing had happened, and when a messenger (who was also a priest of the same god)r said they wished the friend hadn't died but that their town was being overrun by Zombies, the Cleric denied that anything had happened and abandoned the town out of anger over being reminded of their friend's death.

Next, the Cleric angrily destroyed city after city out of anger and hatred for the world that abandoned their friend and let them die. After that, the Cleric abandoned their god and made bargains with powers of Evil as they turned on their god and tried to defeat the entity they had once worshiped. Finally, the Cleric became depressed and cried and cried and the whole world was flooded with their magical tears.

Now, the party must trace the path of the fallen Cleric and undue their wrongs step by step. Finally, they must be go to the Cleric's secret home, where they briefly slumber, and convince them to accept and rationalize the loss and go back to the side of good, instead of wasting their now godlike powers for evil. If the characters succeed, they might need to end the Cleric's pacts, or the Cleric becoming good again might do that in itself. This is your choice as the DM.

--

I'm sorry I couldn't think of any more ideas. I hope that the little bit of creativity I was able to scrounge up helped.

Playing on this theme of grief...you could have the relics be keys to unlocking/destroying cages that hold the BBEG's positive emotions. They can defeat the baddie the old fashioned way, by violence, or they can try to restore the baddie's emotions that were stripped away by an evil curse. As for monsters, maybe look at the Sorrowsworn for ideas. Or perhaps they're up against a fallen angel (with empyrean stats) and they need to bring it to repentance somehow - or drag it back to the divine realm for judgment.

Maybe each relic holds a piece of knowledge, a memory, or a part of a spell that can bind the BBEG. Maybe the relics bestow a special, limited-use ability that will enable them to defeat a powerful foe. Not sure what level you'd like them to get to, but take your pick of creatures and homebrew some items that will give them cool powers to use against it. 

maybe the bigbad is some undead power that has been reaching out to corrupt this world from beyond the pale. the five relics are five parts of him that were scattered when he was destroyed long ago. bringing them together would return this evil and loose it upon the world... except that the ritual would leave it briefly vulnerable to complete annihilation. worth the risk?

plenty of room for the grief and woe in the story of the legendary noble protectors of each of these five parts. each fell from nobility and power to obscurity or worse...
 * maybe one went off and interred theirs in a cathedral in a city which, centuries later, has become the topic of dark rumors of missing persons and unholy goings on.
 * another might have decided burial at sea would seal it away. however, that humanoid-centric view failed to take into account the many malignant things that live deep which might have been drawn to it's power.
 * perhaps another began an order of monks who guard a high mountain pass. they'll be shocked to find it missing, the cave where it rested hollowed out from below.
 * another might have sealed themselves into a tower with many incorruptible constructs, living armors, and maybe even mimics. they suspected a corruption might follow and trusted none. that left none to see and warn the mage of their own growing madness and corruption. by the time they realized and locked themselves in at the top of the tower it was long past time to call for help.
 * maybe yet another still never made it to where they were headed, instead fallen prey to a predator in the forest where the corruption went unremarked except to note that some beasts seem more vicious there and some paths have disappeared entirely.
 * or maybe warlords of the plains fight have been fighting over a piece for decades, thinking only that it was a crown of power.
 * perhaps one is actively exploited for its effect on greed and impulse control, housed in a corrupted church to the goddess of luck turned gambling hall. casino heist!

room for every dm to make up their own mini campaign covering a theme of undead, underdark, nomads, druid stuff, etc.

...alternatively, five elemental rings and then the players have to decide if they each get one or if one person is supposed to hold all five. and then how long before someone starts humming the captain planet theme song...

Thank you loads for the help! This is what I came up with for the opening explanation:

King Tidal was the ruler of a vast kingdom. Unlike most rulers that simply take care of cities and their people, he took care of their very timeline, stretching his hands out to insure that the very fabric of space-time stayed intact for the sake of his people.
But there was an evil sorcerer named Helmza that hated the king, for Tidal had banned the citizens from traveling between the timeline, making sure everyone lived normal lives as destiny intended. So Helmza snuck into the throne room in the dark of night, sending him into a spiraling madness using an ancient evil relic of unknown origin.
The people banded together and killed the sorcerer, but for the great king Tidal, it seemed that all hope was lost.
The country spiraled into madness equal to the king’s, with large cracks of time appearing in places far and wide across the kingdom. People could change centuries with one step, only to find it shift again and leave them stranded in a new timeline. The further he fell, the more corrupt and split the kingdom became. Until a team arose from the chaos.
There were five of them, and with this team came five new relics. Crafted to handle the burdens of space and time, the group faced off against the king to bring back peace to their people. It was perilous, and one after the other members of this alliance began to fall, all at the hand of Tidal and his power. It all came down to one last man, a mage, who understood the king better than anyone else in this kingdom.
He was Prince Ocean. Son of Tidal, and heir to the throne.
Ocean fought valiantly against the king, wielding all five relics together to pin him down. Though he knew his father had to be slain, there was still hope that his father’s heart was not as lost as people claimed. But that hope killed him, as Ocean fell to his knees in front of his father, love striking his heart to the ground for the last time.
But Ocean placed a binding spell on his father before he died, causing Tidal to sink into a deep sleep until someone else could cut through his heart or his neck and save the people from the chaos. When they found the prince, the five relics were scattered around his body, followed by a note written from the prince himself.
That’s where this story begins. With Tidal’s slumber the madness also came to a halt, but the timelines were permanently altered. The cracks between the rouge time periods were sealed indefinitely, with only footsteps between centuries.
The relics were scattered in sanctuaries at the end of each “world”, waiting for the next group of heroes to band together and slay the king for good. To find them, our heroes must face off against unspeakable foes, wielding all the courage they have left to overcome the challenges and restore the land to its original glory. But while the people want to see Tidal slain, the prince believed in a different ending… and it’s up to these five adventurers to seek out a solution to this story.

thanks again. My only question now is what to make each of these five relics. Like some said, they could be rings, but I’m also considering other types of armor for different parts of the body. In any regard, I appreciate the help!

This is a beautiful (but saddening) backstory for the campaign. I'm already hoping the characters can use magic to return Prince Ocean to life lol. Though this is a great, well written, history of the world, there are a couple of points I wanted to make:

• Time travel is always super tricky. If you want to incorporate it into your campaign's history, then I would recommend clearly communicating to the players that it is no longer possible to time travel. Also, you might want to ensure that everyone knows the dangers of time travel before they get any ideas... It still might be advisable to do a page or two of rules for traveling through time just in case.
• You don't need to decide what the relics are. Since you guys are taking turns DMing, you can let each person decide what the relic the players need to get when they're in charge is. That being said, it does make sense to decide the relics in advance, too. If I got to decide what they were, I would probably pick body armor, a helmet, a sword, a hammer, and a ring. You could also swap the helmet for something like a shield, or just take a different approach entirely.

Anyways, well done. You've created an awesome backstory. Give yourself a pat on the back.

Thank you! That’s super encouraging and helpful as well, as my next (and hopefully last) dilemma is the relics and their abilities. Here’s my basic idea:

There are five gemstones used to power these five relics. The gemstones hold the power while the relics decide how that power is used. For example:

The Tunic is a body enhancer relic,

The Ring is a weapon enhancer,

The Helmet is a team support relic,

The earrings are a mind enhancer relic,

and The boots are an area affect relic. 

So let’s say one gemstone is used to control the PASSAGE of time (only the king can change time in its entirety).

Tunic: Body moves faster than time (1 turn=2 moves)

Ring: Weapon emits fall-off damage (two turns after the player, the target is hit again with disadvantage)

Helmet: Team is safe against time-based attacks (King Tidal’s attacks, to be specific)

Earrings: Player can see how close the enemy is to death (or they could predict it’s next move?).

Boots: Anything determined to be a foe within a ten foot radius of the player is slower and rolls with disadvantage.

That’s the idea, but I need to figure out what powers each stone possesses. I also have to home brew the final boss in such a way that certain attacks are harder to defend against if, per se, the time stone isn’t in the tunic, as defense against the time attacks would become much more difficult. So the five stones and the boss are really the two last things. If there’s anymore ideas I’d love to hear them, and thanks again for everything so far. Really excited to see this come to life.

Edit: I’m also wondering if I should tell the players that this is how the relics work… Because they are interested in inserting their own relics into their stories and I have to decide what’s best.

Quote from Digidax_Gamer >>

Thank you! That’s super encouraging and helpful as well, as my next (and hopefully last) dilemma is the relics and their abilities. Here’s my basic idea:

<Snip>

That’s the idea, but I need to figure out what powers each stone possesses. I also have to home brew the final boss in such a way that certain attacks are harder to defend against if, per se, the time stone isn’t in the tunic, as defense against the time attacks would become much more difficult. So the five stones and the boss are really the two last things. If there’s anymore ideas I’d love to hear them, and thanks again for everything so far. Really excited to see this come to life.

You don't need to have each relic's powers tied to a gemstone, but there's also nothing wrong with doing so. The abilities for each magic item are cool, though you could also scale them up in power if you wanted to (you might not want to make the boots any more powerful though, they're already quite strong). That being said, I agree with you that King Tidal should be designed in a way so that certain relics are more powerful against him than they might be against a different, random monster.

For instance, you might want to make the boots less powerful against other monsters, but more powerful against Tidal. Perhaps you could have the boots give disadvantage on attacks that deal a certain type of damage that the King uses a lot. You also might want to elongate the range of 10 feet, because it doesn't really matter that King Tidal is slower if he's only slowed when some of the players are right next to him. That way, the boots would give the players a boost to escaping Tidal if everything goes terribly wrong and they're about to be TPKed.

Make Tidal a big, high CR boss with a lot of hit points, damage potential, and cool unique abilities. Make the terrain of the battlefield matter, because it will create a more interesting and unusual encounter, as opposed to a "Run up and hit things" type of fight.

Quote from Digidax_Gamer >>

Edit: I’m also wondering if I should tell the players that this is how the relics work… Because they are interested in inserting their own relics into their stories and I have to decide what’s best.

If you want to decide what the magic items do, then you should tell whoever is running the adventure how they work and what that item's stats are. That being said, there's nothing wrong with them designing less powerful magic items and inserting them into their adventures.

Quote from Digidax_Gamer >>

Thank you loads for the help! This is what I came up with for the opening explanation:

King Tidal was the ruler of a vast kingdom. Unlike most rulers that simply take care of cities and their people, he took care of their very timeline, stretching his hands out to insure that the very fabric of space-time stayed intact for the sake of his people.
But there was an evil sorcerer named Helmza that hated the king, for Tidal had banned the citizens from traveling between the timeline, making sure everyone lived normal lives as destiny intended. So Helmza snuck into the throne room in the dark of night, sending him into a spiraling madness using an ancient evil relic of unknown origin.
The people banded together and killed the sorcerer, but for the great king Tidal, it seemed that all hope was lost.
The country spiraled into madness equal to the king’s, with large cracks of time appearing in places far and wide across the kingdom. People could change centuries with one step, only to find it shift again and leave them stranded in a new timeline. The further he fell, the more corrupt and split the kingdom became. Until a team arose from the chaos.
There were five of them, and with this team came five new relics. Crafted to handle the burdens of space and time, the group faced off against the king to bring back peace to their people. It was perilous, and one after the other members of this alliance began to fall, all at the hand of Tidal and his power. It all came down to one last man, a mage, who understood the king better than anyone else in this kingdom.
He was Prince Ocean. Son of Tidal, and heir to the throne.
Ocean fought valiantly against the king, wielding all five relics together to pin him down. Though he knew his father had to be slain, there was still hope that his father’s heart was not as lost as people claimed. But that hope killed him, as Ocean fell to his knees in front of his father, love striking his heart to the ground for the last time.
But Ocean placed a binding spell on his father before he died, causing Tidal to sink into a deep sleep until someone else could cut through his heart or his neck and save the people from the chaos. When they found the prince, the five relics were scattered around his body, followed by a note written from the prince himself.
That’s where this story begins. With Tidal’s slumber the madness also came to a halt, but the timelines were permanently altered. The cracks between the rouge time periods were sealed indefinitely, with only footsteps between centuries.
The relics were scattered in sanctuaries at the end of each “world”, waiting for the next group of heroes to band together and slay the king for good. To find them, our heroes must face off against unspeakable foes, wielding all the courage they have left to overcome the challenges and restore the land to its original glory. But while the people want to see Tidal slain, the prince believed in a different ending… and it’s up to these five adventurers to seek out a solution to this story.

thanks again. My only question now is what to make each of these five relics. Like some said, they could be rings, but I’m also considering other types of armor for different parts of the body. In any regard, I appreciate the help!

Just noticed this thread, so I might be late with these suggestions, but:

- this is a cool idea, but I think this backstory would be better framed as a myth or fable usually dismissed as a tale for children, rather than actual book history. Strip it down to only the essential facts the party will need (five relics now scattered, the prince being the last one standing and believing his father was not lost in madness forever) once they realize there's some truth to it (maybe because King Tidal is beginning to stir and time is getting funky again)

- I would think outside the box on the relics and not make them ye olde rings of power, gemstones, or weapons/armor. They aren't intended for combat, they're intended to repair time. Go the Indiana Jones and the Last Crusade route -- the relics aren't the fanciest or most impressive-looking things because they weren't made to be fancy or impressive, they were made to be functional. Maybe one's a hourglass, another a spindle, etc. They can still grant combat advantages for the big boss fight once found, but part of the puzzle should be figuring out exactly what purpose they were created for other than to be weapons, and why Prince Ocean's plan didn't work (maybe it has something to do with that original evil relic... whatever happened to it?)

Perhaps a helmet that represented the kings sanity before he fell that allows the wearer to hold some control over the power the king once had(I'm being vague because I'm unsure what the king could do).

Quote from BoringBard>>>>

You don't need to have each relic's powers tied to a gemstone, but there's also nothing wrong with doing so. The abilities for each magic item are cool, though you could also scale them up in power if you wanted to (you might not want to make the boots any more powerful though, they're already quite strong). That being said, I agree with you that King Tidal should be designed in a way so that certain relics are more powerful against him than they might be against a different, random monster.

For instance, you might want to make the boots less powerful against other monsters, but more powerful against Tidal. Perhaps you could have the boots give disadvantage on attacks that deal a certain type of damage that the King uses a lot. You also might want to elongate the range of 10 feet, because it doesn't really matter that King Tidal is slower if he's only slowed when some of the players are right next to him. That way, the boots would give the players a boost to escaping Tidal if everything goes terribly wrong and they're about to be TPKed. >>

Yes yes and further yes. All of this is super helpful. Here’s the list idea I came up with, and there are some pretty crazy ideas in here…

Crystal of TIME

Tunic: Body moves faster than time (1 turn = 2 moves)

Ring: Weapon emits fall-off damage (two turns after the player, the target is hit again with disadvantage)

Helmet: Team is safe against time-based attacks (King Tidal’s attacks, to be specific)

Earring: Player can transfer their mind to another players, allowing them to copy someone else’s move. The cooldown time is equal to the spell level.

Boots: Anything determined to be a foe within a ten foot radius of the player is slower and rolls with disadvantage.

Crystal of Fate

Tunic: Player is able to bring themselves back to half health after becoming dbno. The Crystal will not work again until after a long rest.

Ring: Life drain- When a player hits the enemy head on successfully, they gain hit points equal to half of what was dealt to the enemy. 

Helmet: All players gain seventeen extra hit points.

Earring: Thrice in a battle, the player may ask to know the enemy’s hit points. The DM will tell the player a percentage.

Boots: Player creates a ten foot circle of rough terrain. It does not affect the player.

Crystal of Passing

Tunic: If health drops below 25%, attacks do double the damage.

Ring: Weapon gains decay damage.

Helmet: If a team member is down, other members roll with advantage.

Earring: Impending doom- advantage on attacks

Boots: Sinking sand- Player can merge into shadows, transporting themselves up to fifty feet away.

Crystal of Captivity

Tunic: Grants user a defensive shield, fully blocking one attack of choice. Four round cooldown.

Ring: Call your weapon back at will. Arrows included.

Helmet: Group has advantage when rolling against a binding spell

Earring: Player can lock the last move used by any entity for one round, until the start of its next turn. One turn cooldown. Cannot be stacked.

Boots: Chains spin in a seven foot radius around the player. If attacked head on, the enemy has to roll a 1d20 to avoid losing its weapon to the chains.

Crystal of Discord

Tunic: Player gains the shapeshifting spell. Usage is equal to that of their level.

Ring: Roll a 1d10 when attacking. Add the damage type represented by the dice along with the previous one. If a ten is rolled, the spell fails.

[1] Acid, [2] cold, [3] fire, [4] thunder, [5] lightning, [6] necrotic, [7] poison, [8] psychic, [9] radiant

Helmet: Initiative 66- Players can override the initiative to attack at the same time in succession. Enemies attack after the players based on their initiative difference. Three round cool down.

Earring: Player can inflict madness on one entity, giving them disadvantage on attacks but a plus one modifier if hit effectively. Does not work on someone who already has madness.

Boots: Mob effect- Player can create a hallucinatory “mob” made up of people they’ve met along the journey. The mob will surround the player in a five foot radius, giving them advantage when being attacked head on.

They’re all pretty out there, but I tried to keep with a similar approach for each relic’s response to the different crystals.