Ortho Engineer

Spellcaster. The Ortho Engineer is a 7th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 14; +6 to hit with spell attacks). The Ortho Engineer has the following spells prepared:

Cantrips (at will): Chill Touch, Mage Hand, Toll the Dead, Prestidigitation

1st level (4 slots): Cause Fear, False Life, Inflict Wounds, Ray of Sickness

2nd level (3 slots): Blindness/Deafness, Gentle Repose, Ray of Enfeeblement

3rd level (3 slots): Animate Dead, Bestow Curse

4th level (1 slot): Blight

Augment Undead. As a ritual with a casting time of one hour, the Ortho Engineer can enhance an undead under its control. The Ortho Engineeer must either use a corpse or another undead minion as the material components for this ritual, which are destroyed. 

Boneclaw. Melee Weapon Attack: +4 to hit, reach 5 ft., one target: Hit: 5 (1d4+2) slashing or piercing damage and the target must succeed on a DC 15 Constitution save or take 18 (4d8) Necrotic damage.

Animate Skeleton (3/day). The Ortho Engineer raises a corpse within ten feet as a skeleton. The Ortho Engineer can use a bonus action to command the skeletons, and they will continue to follow its command until the command is completed or the Ortho Engineer orders them otherwise. The skeletons remain under the Ortho Engineer's commands for one hour. The Ortho Engineer can maintain control of the raised skeletons through  Animate Dead