They are earth mud doggies
Perhaps they could have a rare chance to drop magic mud aswell, it'd give people more incentive to black beast raid
I agree, Black Beasts don't have a 'drop' of their own, per say. Only those Black Books which are used once and discarded.
So how about making LV 55+ Black Beasts have a chance to drop ''Magic Mud''?
This is a possibility. One thing that's been on my list for a while is 'escalations' for Black Beast attacks to give incentive for people to do them and try to rack up a high kill count aside from bragging rights. This might be a good way to do it.