The last organization affiliated with the Villain League is

It is where the black sheep of society that are the stray monsters gather.

Rights for monsters

Their goal is to dominate the world in order to create a society for these monsters.

So, the Monster Benefit Group

requested us to train a new monster by putting him through actual combat.

Why us specifically?

They told me...

Almost all the monsters at the Benefit group are veteran, lone-wolf kinda monsters...

So they don't really have anyone to help train new monsters... that's what they said.