You have to be really creative to not repeat enemies with a different color pallet, like in almost every RPG. I remember playing every SNES rpg and seeing the same enemies mid game with different colors, even in PSone and PS2. Nevertheless making antagonists that are appealing must be a difficult task. Right now I'm Playing Shin Megami Tensei IV, and I haven't seen a rehash of a demon, I think they are all unique and that makes me want to progress to know and catch em all!
There have been so many enemies that have impacted my life. For example Reapers in ME, the way they were presented as al almost godlike cyber race made me feel respect for them from the start. Also the enemies in Xenogears, they were so many characters in xenogears and all of them well explained but the enemies shined a lot. DEUS, GRAHF, MIANG the KRILLIAN EMPIRE, they were enemies so well thought, I feel like replaying Xenogears for the forth time.
Between Dragon Quest and Final Fantasy I think I like DQ enemies more. Don't get me wrong, Marlboros, Tornberries and the bunch are always cool, but there is something in DQ that draws me to not care if the enemies get reused with different colors like 15 times.
So, what are you favorite enemies/antagonists in a video game?