Wasn't he though? insane as he was, he still had a similar power as Yu. Even though it was corrupt and stuck with one overpowered Izanagi Pico.

But he didn't kill YHVH

Neither did most things. Also, last I checked, no ones truly killed YHVH, as the figure that keeps popping up is just a fragmented shard of the whole. (SMT4:A)

That's true but i meant if he was a godslayer in mainline