Thrashing Assault - Where To Learn?

I noticed on bg-wiki that this spell is learned from Meeble's. Where do these spawn? I have heard in campaign ops? If this is the case, what is the fastest way to get to them? I am only about 20ish missions into WotG and prefer not to get too involved honestly (returning player, that expansion made me quit in the first place).

Thanks!

Meeble Burrows Adjunct expedition 1 in Batallia. 12 spawns and you don't need to farm any other fights to get access.

Thank you!!!!!