The Ferryman

You have pledged both your sword and soul to Charon, the ferryman of the dead. From this deal, you gain immense power, but also a duty. All Charon wants is for the dead to be properly sent off to their afterlife of choice. You will gain favor by helping with burial rights, defending grave sites, and killing those who would disturb such sacred ground. You lose favor by robbing graves, desecrating bodies, and leaving bodies unattended after death. It may sound tedious, but such is the price of power. Charon's personality is one of calm indifference. He only gives advice when you really need it (He is on the clock after all), and gives you the respect he feels you deserve (Based on favor). He does not tolerate laziness or disobedience of orders but is fine with failure if it isn't your fault or there is nothing you could have done. While he may be a strict patron, He will genuinely try to help you should something go wrong. Don't expect to talk to him too much though, as he does work 24-hour work days and does not like many interruptions. He always has a total of 25 warlocks at a time.

Charons Blessing

Now that you've become one of Charon's chosen, you immediately gain some benefits. You gain advantage on death saves, gain resistance to necrotic damage, and may summon a small ferry boat with a large, robed, skeleton driving it. The boat has 50hp and dissipates on destruction. The skeleton is immortal and cannot leave the ship and it dissipates when the ship does.

Grace of Charon

You heal for half the necrotic and radiant damage you deal. You gain (Warlock level + CON modifier) temporary hitpoints when you reduce a creature to zero hitpoints.

Ferryman's Acolyte

Starting from 6th level, allies you revive with the "Help" ability return with 30% of their max HP restored. You may also use the "Help" ability as a bonus action and it has a range of 15 feet. When you revive an ally, you heal hitpoints equal to their level. You are resistant to radiant damage now.

Boon of the Styx

Starting at the 10th level, allies you revive return with 50% hitpoints, and the range of help is increased to 30ft. You are now immune to necrotic damage and any necrotic spells crit on a 17 or higher. 

Paragon of the Five Rivers

Each long rest you may use each of these abilities once.

 

The First: Styx: You may point at a creature you can see. Watery figures rise from the ground, grapple your opponents, and attempt to drag them under. They may make a CON save ((DC = Warlock level + CON modifier) Failing three checks in a row drags the creature down and kills them instantly. It may also be used as a 25ft AOE, without the drag under mechanic.

The Second: Lethe: You point at a spot you can see and a cloud of mist expands from that point. Every entity must make a CON save (DC = Warlock level + CON modifier). Any entity who fails the saving throw forgets everything that has happened to them in the past week and is stunned until a creature uses a "Help" action on them.

The Third: Acheron: You extend your hand in front of you, and a tidal wave of dark purple water crashes forward from it (7x40ft wave). any enemy caught in the swell takes 7d10 Psychic damage. This ability ignores psychic resistance/immunity.

The Fourth: Phlegethon: You may point at an area within sight and that area explodes with flaming liquid. If it has less than 50 hp and fails a CON save (DC = Warlock level + CON modifier), the area may be a creature, which will instantly die. If it succeeds they just take normal damage and it still explodes from that creature. No matter where it is any creature within 30ft takes 12d8 fire damage (this damage ignores damage adjustments (Resistances and immunities)).

The Fifth: Oceanus: Drag you and up to three target creatures into a demi-plane-like expanse for 10 turns or until you perish. The demi-plane resembles a massive red river that's able to be walked on, with burning forests on either side and a large red ouroboros symbol slowly spinning where the sun should be. As long as you remain in this demi-plane, you are resistant to all attacks, but you are vulnerable to all attacks until your next turn when you reappear. Any corpses left in the demi-plane heal you for 2d8 hitpoints, but any non-organic materials or items on them are sent back.