Monsters origin ever explained?

[Headhanger]

It seems to me that the humanoid creatures are Alexander's "servants". He writes in one memoir that he may need to "create" or "make" more of them.

I would guess that he submitted people to variour alchemical concoctions and the brutes, etc. are the result.

The water monster has a proper name, beggining with a K, but I don't remember it. It's on

Spoiler below!

Agrippa's shopping list. It's from another world, apparently, perhaps the one that Alexander and Agrippa are trying to reach.