Beath, The Black Machine

Touch of Death. When you hit a creature with a melee attack, you can spend a Channel Divinity use to deal an extra 13 points of Necrotic damage.
Darkened Loyalty. Whenever you cast a spell that would deal Radiant damage, it now deals Fire damage. Any healing spells Beath cast can only affect Undead, Fiends, and Monstrousities. 
Lucky. When you roll a 1 on the d20 for an attack roll, ability check or saving throw, you can reroll the die and must use the new roll. 
Gunner. You ignore the loading and reloading property of firearms. Being within 5 ft. of a hostile creature doesn't impose disadvantage on ranged attacks. 

Spellcasting. Beath, The Black Machine, is a 4th-level spellcaster and 3rd-level Artificer. Its spellcasting ability is Intelligence (spell save DC 15, +8 to hit with spell attacks). Beath has the following spells prepared:
Cantrips (at will): Fire Bolt, Green-flame blade, Toll the Dead, Word of Radiance

1st level (4 slots): absorb elements, Bane, Command, command, Cure Wounds, Feather Fall, Guiding Bolt, Inflict Wounds, Ray of Sickness, Sanctuary, Shield of Faith

2nd level (3 slots): Blindness/Deafness, Hold Person, ray of enfeeblement, Silence, Sudden Slide

3rd level (3 slots): -Only for Upcasting-

Longsword. Melee Weapon Attack: +3 to hit, reach 5 ft., 1 target. Hit: 11 (1d8+3) Slashing damage. Bonus action, add +4 (1d8) Fire damage. Second target takes 11 (1d8+4) Fire damage.
Mechanical Leg. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 8 (2d4+4) Bludgeoning damage. Target must succeed DC 12 STR save or be knocked prone. Can only be used 1 per turn. 

Dueling Pistol. Ranged Weapon Attack: +8 to hit, reach 40/120 ft., 2 targets. Hit: 13 (2d8+5) Piercing damage. Beath can make 2 Pistol attacks per Attack Action. 

Inflict Wounds. Melee Spell Attack: +8 to hit, reach 5 ft., 1 target. Hit: 15 (3d10) Necrotic Damage.

Guiding Bolt. Ranged Spell Attack: +8 to hit, reach 120 ft., 1 target. Hit: 12 (4d6) Fire damage. 
Ray of Sickness. Ranged Spell Attack: +8 to hit, range 60 ft., 1 target. Hit: 8 (2d8) Poison damage.
Ray of Enfeeblement. Ranged Spell Attack: +8 to hit, range 60 ft., 1 target. Target deals only half damage with STR-based attacks. 
Fire Bolt. Ranged Spell Attack: +8 to hit, range 120 ft., 1 target. Hit: +10 (2d10) Fire damage.

Spells. sanctuary

Harness Divine Power. Once per Long rest, you expend a use of your Channel Divinity to regain one expended spell slot of up to level 2

Spells. absorb elements, feather fall, shield, Sudden Slide

Law of Spiders. When an ally within 60 ft. of you falls to zero hit points, Beath can use their reaction to take (X) amount of Necrotic damage (ignoring Resistance and Immunity) and gift their ally temporary hit points equal to the damage taken.