Bone Mech

Curse of Vitality. Every action/legendary reaction/reaction performed by the controller of the bone mech takes five away from their VP (vitality points). If the user reaches 0 VP they die. The user regains 5 VP per hour outside of the bone mech.

Legendary Resistance (3/Day). If the bone mech fails a saving throw, it can choose to succeed instead.

Rejuvenation. If the bone mech has a phylactery, the destroyed mech gains a new suit in 1d10 days, regaining all its hit points and becoming active again. The new body appears within 5 feet of the phylactery.

Turn Resistance. The bone mech has advantage on saving throws against any effect that turns undead.

Boneth Deleteth. Melee Spell Attack: +9 to hit, reach 15 ft., one creature. Hit: 10 (3d6) necrotic damage. The target must succeed on a DC 18 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Cartilage Shield. The bone mech may roll a d4. If the result is a 1, the mech takes double damage from the current/next attack against it. If the result is a 2, the mech takes half damage from the current/next attack against it. If the result is a 3, the mech takes a fourth of the damage from the current/next attack against it (round up). If the result is a 4, the mech takes no damage. 

The bone mech can take 2 legendary action, 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. The bone mech regains spent legendary actions at the start of its turn.

Boneth Deleteth (Costs 2 Actions). The bone mech uses its Boneth Deleteth action.

Frightening Gaze (Costs 2 Actions). The bone mech fixes its gaze on one creature it can see within 50 feet of it. The target must succeed on a DC 16 Wisdom saving throw against this magic or become frightened permanently as long the mech is in view. The frightened target can repeat the saving throw at the end of each of its turns, ending the permanent effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to the bone mech's gaze for the next 24 hours.

Disrupt Life (Costs 2 Actions). Each non-undead creature within 20 feet of the bone mech must make a DC 18 Constitution saving throw against this magic, taking 15 (6d6) necrotic damage on a failed save, or half as much damage on a successful one.