Blue

Siphon. Whenever Blue does 15 or more Psychic damage in a turn, he creates one psyspirit minion.

 Scream of 10,000 Pounds of Steel. After Blue reaches 65 HP or lower he releases a horrid screech of pure mind and impure form creates destruction to all those near. Any creature within a 30ft radius sphere of Blue must make a DC 17 Intelligence saving throw or take 18 psychic damage and become frightened. 

After Scream of 10,000 Pounds of Steel is used, Blue enters a new phase where his movement speed is 0, his AC is buffed to 17, and he creates an area around him 30ft radius, immediately pushing them back that much, in this area the scream is so powerful that it pushes back on the players, halving their movement. Also when they enter the zone, at the end of every round all players in the zone must make a DC 14 Strength Saving Throw or be pushed back 10 ft.

Mind Nail. Melee Weapon Attack: +4 to hit, reach 5 ft., 1 target. Hit:  (1d8 + 4) [psychic] damage and every round after the target rolls a wisdom saving throw (DC 14) or take 1d6 psychic.

Crowd of Whispers. Ranged Weapon Attack: +4 to hit, range 20/60 ft., 1 target. Hit:  (2d6 + 4) [psychic] damage and the target must make an intelligence saving throw (DC 15), on a fail they have disadvantage on their next action or they have to choose between action, bonus action, or reaction.

Psyslam. As a bonus action, if a target is within 5 feet of Blue he can make a melee attack roll against them using his intelligence modifier. If the attack hits the target takes 1d8 force damage and is pushed back 5 feet.

Twitch. Once per round Blue may twitch, the psychic powers around him force his body to turn inhumanly. This imposes disadvantage to one attack roll.