Magic Resistance. The hooded Isodhi has advantage on saving throws against spells and other magical effects.

Seven Heads. The Isodhi has advantage on saves against being blinded,  charmed, deafened,  frightened, stunned, or knocked  unconscious.

Water Breathing.  The Isodhi has the ability to breath both air and while under water.

Multiattack. The yuan-ti Isodhi makes one Flurry attack and one Constrict attack, or it can make one poison "breath weapon" attack.

 Flurry of Bites. Melee Weapon Attack: +10 to hit, reach 15 ft., one creature. Hit: 27 (6d6 + 6) piercing damage, plus 14 (3d6) poison damage.  

Constrict. Melee Weapon Attack: +10 to hit, reach 20 ft., one Large or smaller creature. Hit: 16 (3d6 + 6) bludgeoning damage, and the target is grappled (escape Strength Save DC 16). Until this grapple ends, the creature is restrained, and continues to take damage each round.  The Isodhi can only constrict one creature at a time.  

Poison Cloud Spray (Recharge 5–6). Constitution Saving Throw: DC 18, each creature in a 45-foot Cone. Failure: 36 (8d6) poison damage, and they are blinded until the start of the Isodhi's next turn. Success: Half damage and no blindness.

"Trust In Me, Just in Me".  The Isodhi has an ability to mesmerize a single creature with its gaze.  At the end of another creature's turn, the Isodhi can attempt to gain control of a creature's motivation and direction.  A creature within 30 feet that the Isodhi chooses must make a Charisma saving throw (DC 18) or become mesmerized by the Isodhi.  Unless they receive any type damage from the Isodhi, they will not actively attempt to harm the yuan-ti in any way.  They will defend the Isodhi from anyone who is attacking it by placing themselves in harm's way, to include using their reaction.  At the end of their turn, they can attempt to throw off this condition with another charisma saving throw.  Once they have successfully made a saving throw, they are immune to this mesmerizing attack, from this particular Isodhi, for 24 hours.  The Isodhi can only perform this action once per turn.