I want to say Gideon, but it could be because of bias. Not exactly because of Mandalorian, but his other villainous role...at Los Pollos Hermanos, in New Mexico. Lol But he did have a pretty good setup as a threat, despite the disappointment Mando S3 was.

Hemlock may yet win the race, but it will depend on how The Bad Batch S3 plays out. That is presuming we don't see him in any future media afterward. Not to say we know for sure if he will die, or maybe live for the next inevitable animated series to come. We will see.

Hard to say. Gideon was a bad man for sure but hemlock seems pretty creepy and messed up so far and also a very cold-hearted person

Dr. Hemlock seems more like he’s following orders from the Emperor. However, Moff Gideon did everything on his own accord. So I would say Moff Gideon.

I agree with the top reply. Dr. Hemlock isn't completely selfish because he intends to benefit the Emperor's cloning technology. Gideon on the other hand was willing to throw Thrawn under the bus to get what he wanted and uses the Empire as an excuse.

Dr. Hemlock is the Josef Mengele of Star Wars, really. Utterly sick.

Omg I can actually see the resemblance

Good question

Both