Did Tsukiko worship any god(s)?

[Rrmcklin]

I don't get why everyone assumes Rat is the only Evil Southern god. I like to think there is at least 1 per alignment.

Same. It seems similar to assume that Loki is the only Evil God of the North because he's the only one that associated with the Dark One.

Is there direct evidence he's evil at all? He's shown to be a friend of the newly ascended Dark One, but that doesn't prove he's evil.

The gods who associated with the Dark One were explicitly said to be some of the evil ones. So even if you don't want to call that explicit confirmation it, it's definitely evidence. Then again, Loki is the stand out and you still had some people arguing that he might not have been evil either.