The Least of Beasts

The least I know of all the lists of all the beasts there is
It breaks the cysts of all the beasts to cyst itself alone
It's fights alone can make a wreck of all the homes of beasts
It's psyche is great but all the same the least to stand a change
It's never loyal to its kind the least of beasts it is
It's selfish, cruel, it's greed the best it wants the all at once
It's social,wise, and most diverse, its worst has cleaned its best
At least a beast, at least the least of all there is, is man.