[Aebliss]

Originally Posted by MeoTwister5

Nope. Only thing that we can believe is that Ushiromiya Kinzo and Ushiromiya Battler share blood by some means.

Ahhahh ... Okay, here's a cracked theory for all y'all:

Spoiler:

Battler isn't Rudolf's son at all, he's Kinzo's son with his mistress Beatrice. And either she died in childbirth, or else Kinzo for some unimaginable reason convinced her to give up baby Battler to his son Rudolf to raise. Rudolf's such a philandering type, no one would be very surprised if he 'suddenly' presented a child. Battler's sin then becomes either that he killed his mother by being born, or that he completely forgot about her.