How do you create monsters by combining multiple creatures?

No, you can’t do that with random generation. But if you really want to, you can write a script to place a set of random creatures at specific coordinates. By the way, something similar is implemented in the seventh installment; random monsters consist of groups of different creatures. This makes the battles more interesting, but it looks a bit silly when you see that a pile of gold is guarded by skeletons, butterflies, and griffins. What could possibly unite them?! I don’t like this approach.