Demands of Nessus. At the start of each of the cambion’s turns, the cambion can choose one ally it can see within 30 feet of it. The chosen ally loses 10 hit points, and the cambion regains the same number of hit points. If the cambion is incapacitated, it makes no choice; instead, the closest ally within 30 feet is the chosen ally.

Fiendish Blessing. The AC of the cambion includes its Charisma bonus.

Ferocious Surge (Recharges after a Short or Long Rest). When the cambion hits with an attack that isn’t a critical hit, it can turn the hit into a critical hit. 

Fury of the Nine. As a bonus action, the cambion chooses another creature that can see or hear it within 120 feet of it. That creature gains advantage on all attack rolls and saving throws for the next minute or until the cambion uses this ability again.

Infernal Tactics. The cambion has a keen eye for seizing a tactical advantage. Immediately after rolling initiative, it can choose itself and up to three allies it can see if it isn’t incapacitated. It can swap the initiative results of the chosen creatures among them.

Innate Spellcasting. The cambion’s spellcasting ability is Charisma (spell save DC 14, +6 to hit with spell attacks). The cambion can innately cast the following spells, requiring no material components:

3/day: command

1/day each: heroism, spiritual weapon, plane shift (self only)

Multiattack. The cambion makes two melee attacks or uses its Fire Ray twice.

Longsword. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) slashing damage damage, or 9 (1d10 + 4) slashing damage if used with two hands, plus 3 (1d6) fire damage.

Fire Ray. Ranged Spell Attack: +7 to hit, range 120 ft., one target. Hit: 10 (3d6) fire damage.