Maybe I'm autistic, but the timeline drawn there seems a bit odd then>T-15y - Shamiko, Momo, Mikan and the like are born>??? - Momo's parents die/disappear>??? - Sakura takes Momo as her little sister apprentice>??? - Shamiko goes through early childhood spending much of her time in hospital>??? - The above forces Yuko family to move to Sakura's town to seek her aid>??? - Sakura gets rid of her sub-5 year old apprentice and sends her to a "facility" (I think this would happen before helping Shamiko but we don't know)>??? - Sakura rewires the curse upon Shamiko to try and save her life, enlists Joshua as a help with defending the town>T-10y - Sakura and Joshua have a big fight with ??? and both of them are sealed, in Shamiko and mikan box respectively. Shamiko is slightly better off but still bedridden>??? - Suika shows up to do ??? to the dark clan living in town>T-6y - 9 year old Momo returns to the town to look for her sister that told her off 4 years ago.>T-6y - Momo runs into Suika and unwittingly helps her achive her goal of ???ing the demons in the town>??? - Momo fights Suika and drives her out of town, at the cost of permanent scars on her body and spiralling depression after witnessing the ???ing inflicted unto the dark clan>T-6 chapters - Shamiko awakens
This whole mess doesn't even include Mikan and her role in this, how Uga came to be, how the Hinatsuki mikan factory got obliterated by Momo in a fight with ???. Not to mention whichever reincarnation of Ogura this is/was. It would felt more coherent if Momo was asked to leave at a bit older age (maybe ahead of the big fight with ???) and returned faster. A 9 year old that comes back after 4 years of exile seems really bizzare.