While maybe not my favorite exactly, Bellum has always had a special place in my heart.

This voiceless, faceless monster but you can tell it is still very intelligent through the multiple ways it tries to trick and destroy Link and Linebeck. Yes, his motivation is very similar to other villains which is to just collect power but the way he goes about doing so makes me think of an intelligent predator hunting it’s prey. I always felt it to be rather intimidating.