[MASSIVE SPOILER THREAD] The end

[Solarn]

Honestly, the people who seem to say that torturing and killing innocent men and women while they scream and beg for help is not evil scare me. Whatever his goal was or whatever he started as, Alexander was obviously evil by the time of the game.
Daniel too. It doesn't matter what his original intention was, he tortured people for Alexander, blindly accepting his word on their guilt. In fact, he continued torturing them even after he found out that they were innocent and only decided it was wrong because killing a little girl was still a shock to him. Alexander may have made him a monster, but he was still a monster in the end.
As for Agrippa, we simply don't have enough to go on. We know that he searched for Orbs and that during one such search, he was chased by the Shadow and felt relief when it killed another man instead of him. That's not evil in itself, that's just human weakness. We also know that he worked with Alexander for a while, which means he must have committed some heinous things, but we don't know the extent of their partnership. We know that when they first opened a gate, he let his friend Weyer through instead of Alexander, but we don't know what influenced his decision. Maybe he felt repulsed by Alexander's methods or maybe his friendship with Weyer was just that strong.

But honestly, if one of them had to go through that gate, I'd choose Agrippa. He might have done some horrible things, but I can't see any good in Alexander at all and Daniel is just a smug twit in his ending ("Oh, the whole thing was my purgatory, I triumphed, it was all about me, me me me") so by process of elimination, Agrippa wins. Also, while Alexander just gloats at Daniel if he goes through the gate, Agrippa seems to want to help him, so he's obviously the better person of the two.