[Chirst]

Got additional info about double 7 part 5
credited by oilman

Spoiler for additional info:

Saegusa are from the 3rd lab originally but they started from late period then moved to the 7th lab and used the almost finished research and make a name for them selfs
BTW saegusa was written as three branchs referring the name to the 3rd lab but when going to the 7th lab changed their name to it's known now as seven grasses
And that happened before the 10 clan was formed to as is now