Turn Resistance. Astabar has advantage on saving throws against any effect that turns undead.

Command Poltergeist Astabar can call 3 poltergeist to Aid him in combat.

Undead Fortitude. If damage reduces the zombie to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombie drops to 1 hit point instead.

Spellcasting. Astabar is a 4th level wizard. its spellcasting ability is intelligence (spell save DC 13, +4 to hit with spell attacks). He has the following wizard spells prepared:
Cantrips (at will): chill touch, mage hand, prestidigitation
1st level (2 slots): false life, ray of sickness
2nd level (1 slots): ray of enfeeblement, blindness/deafness

Slam. Melee Weapon Attack: +3 to hit, reach 5ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage.

Club. Melee Weapon Attack: +2 to hit, reach 5ft., one target. Hit: 5 (1d6 + 2) bludgeoning damage.

Paralyzing Touch. Melee Spell Attack: +3 to hit, reach 5 ft., one creature. Hit: 6 (2d6 + 2) cold damage. The target must succeed on a DC 15 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.