Belin Daruse

Regeneration. Bellin regains 10 hit points at the start of its turn. If the troll takes acid or fire damage, this trait doesn't function at the start of the troll's next turn. The troll dies only if it starts its turn with 0 hit points and doesn't regenerate

Innate Spellcasting. Bellin’s innate spellcasting ability is Intelligence (spell save DC 20). He can innately cast the following spells, requiring no material components:

At will: Acid Splash (4d6+6 acid damage), mending , cure wounds, animate dead

3/day each: blur, haste, Fabricate

1/day each: antimagic field, Heal cloudkill, Death ward

Legendary Resistance (3/Day). If Bellin fails a saving throw, he can choose to succeed instead.

Magic Item Savant. Bellin can use a bonus action to interact/use any magic item he has at his disposal. In addition he can make one command to any of his underlings/constructs. Bellin will always have on him 5 potions and 5 spell scrolls of the DM’s Choice. 

Master of the Arcane. Unless Bellin wishes to be affected, Bellin is immune to spells of 2nd level or lower. He has advantage on saving throws against all other spells and magical effects.

Multiattack. Bellin makes 3 attacks one longsword attack and 2 pistol shots.

Longsword. Melee Weapon Attack: +17 to hit, reach 5 ft., one target. Hit: 11 (1d8 + 7) piercing damage plus 17 (3d6+6) acid damage, and the target has disadvantage on the next attack roll it makes before Bellin’s next turn.

Pistol. Ranged Weapon Attack: +14 to hit, range 80 ft., one target. Hit: 12 (1d10 + 6) piercing damage plus 11 (1d6+6) fire damage.

Spellbottle: when you see a creature casting a spell within 60 feet of you, you can open the bottle as a reaction in an attempt to interrupt the spell. If the creature is casting a spell of 3rd level or lower, the spell has no effect, and it is stored in the bottle. If it is casting a spell of 4th level or higher, make an Intelligence check. The DC equals 10 + the spell’s level. On a success, the spell has no effect, and it is stored in the bottle.

Bellin can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Lazav regains spent legendary actions at the start of his turn.

Attack. Bellin releases spell in spell bottle.

Cast a Spell (Costs 2 Actions). Bellin casts one of his innate spells.

Potions (Costs 3 Actions). Bellin consumes a potion of rare or lower of the DM’s Choice.