there are 10 original characters, but we do not care nearly enough about them.
apparently, 5 other idolmaster girls are ripping off the band "The walk of Chihaya Kisaragi" (which does contain chihaya kisaragi in it, it's not an idolmaster group) except with their own members. let me introduce you to them.
generic I D O L M A S T E R girl 1 sayoko takayama
a 17 year old teenager who looks like a nerd because she's one. but she has an energetic side.
generic idolmaster girl 2 arisa matsuda
the girl who sang "chou jou genki idol chang." has red hair and two pigtails.
generic IdolMaster girl 3 chizuru nikaido
she has a queen aura like chihaya kisaragi from the parable of chihaya kisaragi, but she is not chihaya kisaragi. and therefore she isn't cool. fake celebrity...
generic IDOLMASTER girl 4 mirai kasuga
Her name means future spring days. Anything else in mind?
the most generic i.d.o.l.m.a.s.t.e.r. girl anna mochizuki
always sleepy and tired. also has a nintendo switch.
together, they're trying to rip off chihaya kisaragi. this can't happen! we've gotta get takane shijou and the others!
no wait, "The walk of Chihaya Kisaragi" contains I D O L M A S T E R characters... it's a crossover!!
it's all your fault takane shijou