I've seen a similar cel and I think it was claimed to be from episode 8, but I haven't watched much Weiß yet so I don't know for sure. If I haven't watched it, why do I own two cels of the same character?

It's a simple answer... Seki Tomokazu. I got voted in as Ken for a Weiß cosplay group about half because of that factor alone, thoroughly enjoyed doing the costume despite my frightening experiences with "yaoi-Omi" at the con... and then went out and found this cel for sale in someone's gallery. End of story.

The thing I like about this cel is that you can see more of Ken's costume in it.

Hey, did I mention that I still have the bugnuk I made, and that's sitting like a trophy on my bookcase? ^^;;

At half price, I couldn't say no to an OP cel of Ken kicking ass. It's not the best of cels in terms of aesthetics, but it's from Velvet Underworld, and that song kicks ass. ^^;