Homebrew
Devil's Sight. Magical darkness doesn't impede the abishai's darkvision. Magic Resistance. The abishai has advantage on saving throws against spells and other magical effects. Reckless. At the start of its turn, the abishai can gain advantage on all melee weapon attack rolls during that turn, but attack rolls against it have advantage until the start of its next turn.
Multiattack. The abishai makes one Bite attack, one Claw attack, and one Longsword attack. Bite. Melee Weapon Attack: +6 to hit, reach 1 sq., one target. Hit: 5 ( 1d4+3 ) piercing damage plus 3 ( 1d6 ) cold damage. Claw. Melee Weapon Attack: +6 to hit, reach 1 sq., one target. Hit: 8 ( 1d10+3 ) slashing damage. Longsword. Melee Weapon Attack: +6 to hit, reach 1 sq., one target. Hit: 7 ( 1d8+3 ) force damage, or 8 ( 1d10+3 ) force damage if used with two hands.
Vicious Reprisal. In response to taking damage, the abishai makes one Bite attack against a random creature within 1 square of it. If no creature is within reach, the abishai moves up to half its speed toward an enemy it can see, without provoking opportunity attacks.