Rogue Level	Feature
3rd	Black Flame, Purify (1/rest), Spellcasting
9th	Purify (2/rest), Zealous Heart
13th	Fateful Stride
17th	Purify (3/rest), Unholy Immolation

Black Flame.

Those that follow the path of the Black Flame Zealot forsake all care, and love, and compassion to become an instrument of vile hatred and corrupted life. Beginning at 3rd level when you chose this archetype once per short or long rest you can coat your weapons in black flame, dealing necrotic damage instead of your normal weapon damage for 1 minute.   Additionally, any spell you cast, ability or magic item you use that would deal radiant or fire damage, instead deals necrotic damage. When you deal deal necrotic damage, creatures that are resistant to necrotic damage take full damage from this feature, and creatures that are immune to necrotic damage instead take half damage from this feature.  

Purify.

Beginning at 3nd level when you attempt to sneak attack a target you can sacrifice a spell slot of first level or higher. If the attack hits all of the damage is necrotic damage, you deal an additional 2d6 damage per level of the spell sacrificed, and the target must make a Constitution saving throw or be ignited in black flames. At the beginning of each of their turns the target takes 1d6 necrotic damage, and can repeat the saving throw at the end of each of its turns to end the effect. If a creature dies while under this effect its body is consumed by the flames and can only be raised from the dead by a resurrection, true resurrection, or wish spell. You can use this ability once per short or long rest at 3rd level, twice at 9th level, and three times at 17th level.  

Spellcasting.

You gain the ability to cast spells.   Cantrips. You learn three cantrips: Sacred Flame and two other cantrips of your choice from the cleric spell list. You learn another cleric cantrip of your choice at 10th level.   Spell Slots. The Black Flame Zealot Spellcasting table shows how many spell slots you have to cast your spells of 1st level and higher. To cast one of these spells, you must expend a slot of the spell's level or higher. You regain all expended spell slots when you finish a long rest. You start with two 1st level spell slots at Rogue level 3, and gain more as you gain more Rogue levels.   Spells Known. You know three 1st-level cleric spells of your choice, two of which you must choose from the evocation and necromancy spells on the cleric spell list. The third can be from any school of magic.   The Spells Known column of the Black Flame Zealot Spellcasting table shows when you learn more cleric spells of 1st level or higher. Each of these spells must be an evocation or necromancy spell of your choice, and must be of a level for which you have spell slots. For instance, when you reach 7th level in this class, you can learn one new spell of 1st or 2nd level. The spells you learn at 8th, 14th, and 20th level can come from any school of magic.   Whenever you gain a level in this class, you can replace one of the cleric spells you know with another spell of your choice from the cleric spell list. The new spell must be of a level for which you have spell slots, and it must be an evocation or necromancy spell, unless you're replacing the spell you gained at 8th, 14th, or 20th level.

Spellcasting Ability. Wisdom is your spellcasting ability for your cleric spells. You use your Wisdom whenever a spell refers to your spellcasting ability. In addition, you use your Wisdom modifier when setting the saving throw DC for a wizard spell you cast and when making an attack roll with one.   Spell save DC = 8 + your proficiency bonus + your Wisdom modifier
Spell attack modifier = your proficiency bonus + your Wisdom modifier

Rogue Level	Cantrips Known	Spells Known	1st	2nd	3rd	4th
3rd	3	3	2	-	-	-
4th	3	4	3	-	-	-
5th	3	4	3	-	-	-
6th	3	4	3	-	-	-
7th	3	5	4	2	-	-
8th	3	3	4	2	-	-
9th	3	6	4	2	-	-
10th	4	7	4	3	-	-
11th	4	8	4	3	-	-
12th	4	8	4	3	-	-
13th	4	9	4	3	2	-
14th	4	10	4	3	2	-
15th	4	10	4	3	2	-
16th	4	11	4	3	3	-
17th	4	11	4	3	3	-
18th	4	11	4	3	3	-
19th	4	12	4	3	3	1
20th	4	13	4	3	3	1

 

Fanaticism.

At 9th level you are immune to the frightened condition, and add your proficiency bonus on saves against being charmed or possessed. At 15th level you have advantage on saves against being charmed or possessed.  

Fateful Stride.

At 13th level you can cast Dimension Door once per short or long rest. If your destination is within 5ft of a source of flame - torch, campfire, fire elemental - you are invisible until the beginning of your next turn.  

Unholy Immolation.

At 17th level once per long rest as an action you can call upon the powers of the Fallen Flame to desecrate a target that you can see within within 90ft. The target ignites in black flames and takes 6d6 necrotic damage, at the beginning of its turn the target can make a Constitution saving throw, on a failed save it takes 8d6 necrotic damage, increasing by 2d6 each turn the creature fails its saving throw. Creatures killed by unholy immolation cannot be raised from the dead or brought back to life except by divine intervention from a greater deity.