No contest Theo. At least with Ian we don't see in explicit detail how horrific his fate is. Theo was left tied to a bed for an entire year to rot while being given the bare minimum food, water for sustenance and given the minimum amount of care just to suffer a slow, painful death without outright killing him and even drugged so much, it helped left him brain dead.

One could actually argue that Peek's fate is worse because of the fact that we viewers have no idea what exactly happened to him; at least Victor was (maybe) put out of his misery once the police found him. Your imagination fills in the blanks with Peek, and it is not pretty.

Either way, Victor and Peek are both great examples of a villain having no real redeeming qualities, while at the same time receiving a fate so objectively horrifying that you can't help but feel sorry for them. At least in my opinion. I used to think otherwise, but now as an adult...

I dunno who the other dude is but I know the Batman beyond guy so I'ma go with him