User blog comment:Godisme/Hear.Fear.Here/@comment-5306073-20120718210744

i would very much doubt it was grimjoww who killed kirge especially since the previous arrancars (i forgot their names) didnt do so well im quessing he is probably aizen. he could have thought of a way of getting out of the seal and since he hates urahara and probably wanted to get his own back on him i also doubt its nel since urahara is friends with ichigo. another possibilty could be that it is one of the royal guards since they are supposed to have a lot of power my final guess is that it could be another sternritter (possibly the leader) since kirge is practically dead and is useless now