Oh yeah, that guy, the one who caused skull fractures with a Bible. The one who was all nice and kind but sent you to the torture chamber to pay for your sins.
Fuckin' Berserk... started as a fairly realistic and slightly stylized medieval warfare story and then they introduced that demon and I was like "Cool, we've got a dash of supernatural here to spice things up." Then bam, a huge can of WTF opened up and we get demon gods, fairies, orks, witches, and just about every fictional creature ever concepted.
I'm pretty sure we were introduced to zombies, fairies and demon gods by the second or third chapter. Kind of early to call it jumping the shark, especially when it must have almost 300 chapters by now.