I just think that while 5th monster would be great. these 4 are beautifully done with a potential to do more. I can think of a bunch right off the bat
Tail whip: 360 swipe
enrage: goliath lights his hands on fire (more so than his heavy animation now) and does bonus melee damage
throw: chuck a hunter you do not like …hank
meteor: fires into the sky. longer its held the more that come down. they come down after the animation ends so goliath can keep fighting.
Graviton: kraken decides he wants everyone to fly. hunters can only move using jetpack otherwise they are free floating
Hold: hold a hunter with 1 tenticle. only light melees work on other hunters. any abilities will not land on the held hunter. IE: no banshee trapping unless u set it up and let it go and hit him towards it. hunter can save himself basically.
Lightning Spasm: Rng lightning strikes significantly weaker.
Grounded: kraken stabs his tail in the ground to stabilize. he now fires projectile melees at an alarming rate. think of DBZ style lol.
Seeker: wraith goes invisible, same mechanics as decoy. except theres no decoy. and wraith gets a bonus on the next melee attack.
empowered scythe:wraith powers up supernova energies into one swipe. its a ranged attack
strafe: wraith gains a low range, quick teleport that leaves behind delayed explosions. maybe 3 teleports?
tackle: instead of abducting and heading back. wraith plows through the hunter and pins him to a surface or x distance.
lava punch: think of falcon punch on a giant behemoth lol
Ragnarock: molten lava spews up from the ground on a target forcing them to keep moving or get hit.
Bob smash: behemoth claps his hands with such force it deals damage and clears traps.
fireworks: while in roll form. behemoth can spew out the secondary part to lavabomb.