[1.2.339] Lionheart Castle?

Each of those mobs have like 5k+ w.att.

Does that mean they hit around 5 ~ 10 times bigfoot damage? Or is that just the ammount of hp damage they inflict on a 1:1 scale?

... It was right there on page 1.

Exactly what it says on the tin.

They will do that number's worth of damage or lower. Never higher.