Keen Smell. The troll has advantage on Wisdom (Perception) checks that rely on smell.

Regeneration. The troll regains 10 hit points at the start of its turn. If the troll takes acid or fire damage, this trait doesn't function at the start of the troll's next turn. The troll dies only if it starts its turn with 0 hit points and doesn't regenerate.

Headband of Intellect (Crown) : This creature wears a Headband of Intellect on one of its heads setting its Intellegence to 20.

Multiattack. The troll makes five attacks: two with its bite and three with its claws.

Bite. Melee Weapon Attack: +11 , {"diceNotation":"1d20+11","rollType":"to hit","rollAction":"Bite"} to hit, reach 5 ft., one target. Hit:  (1d10 + 7) piercing damage.

Claw. Melee Weapon Attack: +11,{"diceNotation":"1d20+11","rollType":"to hit","rollAction":"Claw"} to hit, reach 5 ft., one target. Hit:  (3d6 + 7) slashing damage.

Legndary Actions (2 Per Round)
Extra Claw (1) : Make a claw attack , if it hits target must make a DC 15 Str save or be knocked prone .
Rotating Flail (2) : All creatures within 5ft must make a DC 15 Strength Save or take (3d6) slashing damage and be knocked 10ft away , half as much damage on a success and not knocked back 

Legendary Resistance (3/Day)