It is told later in flashbacks like events with each girl (each have there own friend they confide in or explained the situation too how) be talking alone - this is explained in one of bedrooms and a car drive if I recall right.
dev does story telling similar form to my dorm, the list ect; person -a- shows up most times (out of the blue) from some foreign land usually some event calls on them to help the mc, mc or another character extremely close to mc helps person -a- in a flashback, in this flashback explains how they-their relationship between person -a- and mc was formed and or developed.
This has to be the largest renpy game on here...