User blog comment:TheBody84/Ichigos father being the former Kenpachi/@comment-1654562-20091025101844

he probably knows Ryukken the same way Ichigo knows Uryu. They probably met each other sometime during their "jobs" (killing hollows) and were like /shrug "we are also both doctors, lets kinda get along for the time being" idk /shrug lol but i doubt that the relationship between the two is very important, just like the one between Ichigo and Uryu (not important at all)      =)