love that the whole reaper job-system is based off Actual Roles within concerts, making the entirety of the game an Orchestra that plays the composer's "song"
like konishi's role would be something akin to a "concertmaster" (the conductor's right-hand man) and theres a role called "principal" which are leaders of specific instrumental groups (violins, trombones, etc) which could apply to harriers/wall reapers etc
and in this case id say Kariya is the principal of harriers (given how hes considered everyone's Big Brother, but hes not necessarily leading them per se..)
ive always wondered what 777 was. is he a harrier?? a wall reaper?? the anime gives the impression hes a wall reaper since Hes the one we see giving Out the key pins. so 777 could be the principal of wall reapers (and actually Leads them properly)
in a similar vein, shiba being the "leader" of the shinjuku reapers does Not "confirm" hes the conductor. his role sounds more like the principal of GMs (which is the Concertmaster) so his role is more like konishi's?