Acheron is my favourite character from both a character standpoint as well as a gameplay standpoint in Honkai: Star Rail. I saw it as an opportunity to make a morally grey Paladin Subclass that encouraged a more co-operative playstyle with void mark as a core mechanic of it.
3rd-level Oath of Nihility feature
You gain oath spells at the paladin levels listed in the Oath of Nihility Spells table. See the Sacred Oath class feature for how oath spells work.
| Paladin Level | Spells |
|---|---|
| 3rd | void mark, oblivion |
| 5th | mirror image, misty step |
| 9th | lightning bolt, dispel magic |
| 13th | greater invisibility, dimension door |
| 17th | modify memory, destructive wave |
The following spells may only be cast by Paladins following the Oath of Nihility:
Void Mark 1st level enchantment spell
As a bonus action, you can mark a target within 30 feet with Void Mark. The target must succeed on a Wisdom saving throw or receive a Void Mark Stack. Each successful attack you make to a creature with a Void Mark Stack increases the number of Void Mark Stacks by 1. The Void Mark Stacks last for 1 minute since the latest application.
Oblivion 1st level evocation spell
As an action, make a melee spell attack to a target within range. On a successful hit, the target takes 2d8 lightning damage and each creature within 10 feet of the target takes 1d6 lightning damage. All creatures damaged in this way detonate any Void Mark Stacks on them, dealing 1d8 lightning damage per Void Mark Stack.
At higher levels. Each spell slot above 1st level used to cast this spell increases the initial lightning damage by 1d8.
3rd-level Oath of Nihility feature
You gain the following Channel Divinity options. See the Sacred Oath class feature for how Channel Divinity works.
Call of Nihility. As an action, you can use your Channel Divinity to infuse your weapon with the essence of Nihility. For 1 minute, your weapon attacks deal an additional 1d6 lightning damage and apply a stack of Void Mark to the target.
Shroud of Nihility. As an action, you can use your Channel Divinity to become cover your body with the essence of Nihility, gaining resistance to all damage for 1 minute.
7th-level Oath of Nihility feature
You emit an aura of nihility while you aren’t incapacitated. You and friendly creatures within 10 feet of you gain resistance to lightning and psychic damage, additionally, when a creature with a Void Mark takes damage within this aura, you may designate a creature without Void Mark Stacks to gain a Void Mark Stack within this aura.
At 18th level, the range of this aura increases to 30 feet.
15th-level Oath of Nihility feature
While you are in combat, you can use an action to activate Eclipse Surge. This ability deals 6d8 lightning damage to all enemies within 30 feet and detonates all Void Mark stacks on each enemy. Each detonated stack deals an additional 2d8 lightning damage. If Eclipse Surge detonates 5 or more stacks, you regain 1 expended spell slot of 3rd level or lower.
20th-level Oath of Nihility feature
You transform into the essence Nihility. As a bonus action, you gain the following benefits for 1 minute:
Once you use this bonus action, you can’t use it again until you finish a long rest, unless you expend a 5th-level spell slot to use it again.