Responses
The extra was at the start instead of the end
volume 2 for the Japanese version had an exclusive booklet and koma, I can't see Kodansha US releasing those anytime soon if at all since they don't tend to get the licensing rights for things like that unfortunately.
but if it's the end of vol 2 then shouldn't there be some extras in the end? (i'm greedy i know (￣∇￣"))