Since the king in yellow knows everything did he know that Derek would defeat him? Did he want that??? Did the king want to die experiencing the finest doomed yaoi firsthand??
I think KiY didn't know everything, not in D3rlord3's sense of knowing at least.
As a Cosmic Horror™ King probably is able to a) control his abilities to the max, and b) filter through infinite knowledge. He knows what he wants to know in the moment, and since he believes humans are ants, he didn't bother checking the outcome. He expected to win.
Or, his knowledge was partially cut off, since he was in Minecraft and computers can't store everything the way brains can (to an extent— Derek proves it). KiY had to be the chooser on what he allows the simulations, aka Minecraft world, run without crashing or lagging.
Anyway, King had to be unaware or else he'd just kill Derek before the situation could even lead to Avery meeting D3rlord3.
I know a few depictions, and while I didn't read the original book where King appears, I can't imagine him being actually sadistic or wanting to see others suffer. He could do so, so much worse, and far more damage than that. Yet he actively chooses not to. While, yes, he plays with Derek's mind and tries to trick him by faking Avery — it's clearly because he was stalling and buying more time.
Also, notice how there's not one comment that Avery died in both instances when "he" fell? That he lets the hunger bar regenerate? King doesn't allow anyone to die there. He's not harming them physically and puzzles are solvable.
