[haguruma]

Originally Posted by Jan-Poo

Of course I'm the first to say that Erika is a negative characters. My problem is that she was strongly associated with the search for the truth, which gives the wrong idea that "who searches the truth = Erika", idea that is being reinforced by the fact that the Ange that chooses the truth in the end becomes Erika.

And I still think you are ignoring an important factor here.
There is more than one character in search of truth. Battler, Ange, Featherine, the Witch Hunters, Bernkastel, Erika, they all search for the truth and they all have different approaches.
The important that that has been pointed out by AuraTwilight several times is, that Erika does not search for the penultimate truth, she searches for truth in the sense of indisputable evidence. As long as something cannot be disproven it becomes truth. Erika does not search for the truth, she creates truth from evidence.

How is what Ange did in the trick end connected to gaining the truth?!
She decides to pass judgement because of the evidence she found, okay. We already disclosed that in the case of Amakusa it was probably even justified to kill him out of selfdefense. But the captain?! There was no sufficient prove that he has not been bought by her enemies therefore his innocence is more unlikely than his crime...that is the reason why Ange killed him.
She created the truth that Amakusa and Kawabata sold her over to be killed from evidence she found, but does that make it the truth?!

I also wouldn't characterize Erika as the antagonist of Umineko, she is just the opposing force to Battler's approach. I found both his ear-covering, song-singing ignorance towards the possibility of his relatives crimes, as well as Erika's ruthlesness and incapability to look beyond the mere evidence to be insufficient to reach the truth.
With both you can reach a truth - Like Battler's truth that an additional person who is pure evil killed all his loving relatives or like Ange's truth that her evil aunt Eva killed her innocent family - but the truth is something that exists on more layers than just rationality or emotionality.