The way I see it is that Crayak is essentially the same as Sauron-he wants to destroy everything in the universe(except himself, of course!)and recreate it in his own image. To do that he tries to use more destruction-loving species to wipe out less destruction-loving species until he wipes out the ultimate "winner". Hmmmmmm, ya know what? Maybe Crayak is Sauron!! Think about it-he was banished from the Arda galaxy by Frodo when they cast The Ring into Mt. Doom.
Does that sound like a fanfic or what? 
Actually, if you reread #26 The Attack, that is exactly the motive KA gives Crayak. He wants to recreate the universe in his own image, but he has to destroy in order to rebuild. He's playing a sick game of the Survival of the Fittest.
I don't think what the Ellimist did in #7 The Stranger was sick, in which he supposedly tried to put humans and other Earthly creatures in a zoo on another planet. That wasn't his intention actually. He gave them that proposal as a Trojan Horse. He wanted to save humanity and by showing them what he wanted to save he was able to manipulate them and save it all.
Tricky Tricky Ellimist.
