Quote from Richmillz >>

Once you cast the spe stored in it is it gone or can you cast it agian want to give my fighter this with find steed as I am going for mounted combatant 

 The spell is gone once you cast it. Someone would need to cast the spell into the ring again for your fighter to use it. Using Find Steed (Level 2) as an example, someone could cast it into the ring two times, allowing you to cast it twice before needing a refill. Additionally, lets say you have two casts of Find Steed in the ring, once you use it one time, the original caster could cast it again into the ring, so it is always topped up.

In the instance of Find Greater Steed (Level 4) you could only store one cast of it in the ring.

Ignore me

Soo if I have multiple Spells stored in it, can I cast them all at once? And does it take an Action, Bonus Action or maybe just Item Interaction (not using an Action)?

This ... sounds like a poor choice for a Warlock. A 9th level Warlock would only be able to case 1 5th-level spell into the ring (regardless of the spell's actual level, it would be cast as if from a 5th-level slot, due to Pact Magic). Say I like the shield spell ... I could only put 1 of those in there, as I could only cast it at 5th level.

While an equivalent Wizard could put 5 instances of shield in there, all cast at 1st level.

Sigh.

Guess I need to go make friends with some Wizards ...

give everyone in the party a ring and everyone casts fireball

Hello, if I am wearing this item with spells inside the ring, and I take it off and de-attune from it, then later on that day, re-attune with the ring, will the spells still be inside the ring or does it need to be recharged?

Are there any similar items? Items that hold spells, but are in different forms? (rods, wands, for example?)

Can someone else cast the spell on the ring and give it to someone else? Like if a warlock uses thunder step on in and gives it to like a paladin or barbarian, would they be able to use thunder step that one time too?

Yes

So can you use the spell slots stored in the ring to cast class abilities that use spell slots? like warlocks or paladins?

No, because they aren't spells. The ring stores spells, not spell slots.

Question for my player character in a campaign, I'm a level 2 warlock hexblade and love pumping the ring full of stored shield spells in 2 hours, my question is if I take my 3rd level of warlock both my slots will be cast at 2nd level, but shield cant be upcast, so would it take up two slots in the ring and only allow you to store 2 or would you still cast it and use up both slots but the ring only uses 1 slot of capacity because there's only ever a level 1 shield? Also interested to know for multiclass builds, that 3rd level of warlock is a tough bargain, this might tip the scale

Wait can it just denied wish or any spell other spell if its storage can't hold it with no problem. I mean it says "if the ring can't hold the spell, the spell is expended without effect." This could let a level 1 PC beat Acererak a lich who killed gods and could himself become one if he wanted to. This is only rare if you looked for it you could probably find it.

As an Arcane Archer, find a Bard/Ranger buddy that can cast Swift Quiver into it. At Level 20, you could make 10 attacks in a turn twice per rest (4 with main action, 4 with action surge, 2 with bonus action).

so there is an issue with this, the caster needs to be touching the ring for it to store the spell

"Here you go, a Familiar for you".

Nah, just one hour into the ring

A dry comment would be ignored so lets go with a short story. Here's my take on the ring. For the sake of the narrative:  the players arrive at a level 20 wizard NPC's tower. The wizard's INT stat is maxed out.

Wizard NPC casts a couple of spells into the ring of storing

• Find Familiar (Level 1) takes 1 hour and his level 1 spell slot + components (somatic, verbal, materials)
• Dragon Breath (level 2) takes 6 seconds and his level 2 spell slot + components
• Two Chromatic Orb spells - takes 6 seconds each and two of his level 1 spell slot + components

The ring now has 5 levels worth of spells (find familiar (1), Chromatic Orb(1), Chromatic Orb(1) and Dragon Breath (2) maxing the amount that can be stored in the ring.

Wizard NPC gifts a level 1 party the ring for shits and giggles.

The Rogue decides to attune to the ring on day 1 and attempts to summon a familiar. he uses the ring and takes an hour to "cast" the spell using no components, somatic, verbal or materials. An hour passes and he gets a familiar of his choice and passes the ring to the Barbarian who attunes to it during a short rest.

Later that day the party encounters some... lets say harpies and the normally melee only Barbarian smiles and casts the two Chromatic Orb spells - one during each round picking different elements. the spell atk is calculated using the Wizard NPC casting stats which is +11 calculated by adding the Wizard NPC INT MOD of 5 to the wizard NPC's proficiency bonus of +6. This calculation assumes that the wizard NPC does not have any spell stat boosting item or DM given bonuses.
One harpy manages to survive the battle and flees. The Barbarian confidently yell's, "leave it to me" and tries to cast another Chromatic Orb spell . The ring does not have another chromatic orb spell stored so nothing comes out and the Barbarian instead throws a rock at the harpy killing it (it had 1 hitpoint left).

No one else wanted the Dragon's Breath spell so they gave it to the party Kobald Sorcerer who fancies himself a very small dragon. After attuning to the ring the kobold sorcerer gets into an argument with the Barbarian who keeps telling the kobold that he's not a dragon and wants the kobold to prove that he is. knowing that the kobold can cast spells the barbarian watches for any foul play in terms of incantations or hand gestures. The Kobold only "uses the ring" and casts the Dragon's Breath spell without the barbarian knowing and proceeds to breath fire on the barbarian. the barbarian needs to make a dex save of 19 calculated using 8 plus Wiz INT mod of +5 plus Wizard's proficiency bonus of +6.

Next day the party wants to experiment with the ring and goes to the nearest major settlement to buy spells from NPCs. they sucessfully managed to get a cleric to cast varying levels (under level 5 spell slot) of cure wounds. they discharged the ring completely before asking a Druid to cast a level 6 spell into the ring with no success (given that the ring can only store up to 5 levels worth of spells). They went back to the cleric to get two revivify spells to store into the ring. the first succeeds storing up to 3 levels worth into the ring the second revivify is not stored in the ring given that it would have gone over the 5 level limit. the DM can decide whether the spell fizzles to no effect and spell is lost or the DM could just caution the player before the second revivify is cast or any other variation you can come up with (it's your game).

Straight forward enough right?

Here's where things get tricky:

1. Can the Kobold activate the ring and breath fire on the same turn? RAW suggests a bonus action to cast the spell using the ring and I agree but you can do whatever you want in your campaign. So in this version I'm presenting - the kobold cast the spell using a bonus action and then use an action to breath fire on the barbarian all in one turn
2. Can the kobold use his meta magic on the Dragon Breath spell which was cast using the ring? Given that the item states that all spells caste through this ring is treated as if it is caste by the player attuned to the ring? I'd say yes but once again you can always rule it differently in  your own game. Raw doesn't provide guidance I think as you can argue both cases.
3. Can the kobold cast meta magic spells into the ring? No, by RAW the ring stores the spell, it does not mention anything that would interfere with or modify the spell. Again up to DM discretion
4. can you cast "self" targeted spell into the ring? Yes. By RAW the ring stores the spell if the caster touches the ring while casting the spell.
5. Does the ring store a spell when the caster doesn't intend to? Example: earlier the user of the ring totally discharges it.  While having the ring attuned the user casts magic missiles during battle intending to harm an enemy. RAW suggests that the ring stores the spell instead of it being fired off on the enemy if in contact (specific wording is "touching") the ring but I'd personally rule that it doesn't as i believe it nerfs the item from what is fun.

Thoughts?

Would it be possible to, as a reaction to use the ring to defend/shield myself against a spell cast at me, storing in it instead, and then just hit them with a Reverse Uno card, using this ring, no?

I would say no since the ring isn’t attuned to the caster.