Achaierai
The Achaierai is a large sentient monster bird from Dungeons & Dragons. They were originally Chaotic Evil beings, but in third edition they were retconned into always Lawful Evil and are considered outsiders that hail from Acheron. They have spherical, feathered bodies, with no neck, tiny wings, and four long metallic legs. An Achaierai can't bend down properly to attack grounded folk, so they swipe their legs as their main attack, and they could be crippled if these legs were too injured. Their legs regenerate after a few days, unless they're fully cut off. They can also release poison smoke, which also causes non-Achaierai to also go down with madness and confusion.
They are carnivorous predators that like to torture others. They seek vengeance against others who had a slight against them, but turn against themselves during times of trouble, despite normally going in flocks of two to eight.