[Vallen Chaos Valiant]

From the various internet blogs, about Sekai...

Spoiler for final episode:

It's said that Sekai wasn't pregnant after all, and that it was only a way to trap Makoto. Ironic, then, that this lie was the final straw that caused all the violence. Sekai didn't know that Makoto don't care to be a father, while the lie only enrages the other women to suspect foul play.

All in all, this is a tragic ending, but as it should be; Characters in the show brought this upon themselves.