
Servants can be pulled from any time period in real world to that world, if I remember correctly. The mc is pulled from the modern period. The gangster is came from like the decades before mc time period earlier idk. The birds servant was pulled from the centuries (heian?) before the mc and idols time period. All servants have died at in order to come to that world.

Kotone and Haru is living in the same era... i remember when Kotone recognize Haru's become an actor for a BL movie in their lives... but then Haru die... i guess Kotone die before Haru... but Haru "pop up" on 200 years ago in this isekai, even before Kagetora...
#it would easy to explain it with mouth than fingers, LoL

Kotone, Kagetora and Haru were from same timeline but they were summoned in different years. The order of who died first/summoned first is Haru then he went back then died again but he was held captive by the Qilin for 200 years. Then Kagetora was summoned next and the time Kotone was summoned, Kagetora has been with Wu for 100 years. The only one who did not came from the same timeline is Asagi and Vermillion bird's servant which is from Heian Era which Kotone probably knows from his middle school.
Setting aside Feilong and Kureha's servants, Haru was summoned first then after 100 years Kagetora was summoned another 100 years and Kotone got summoned. Haru did not come back in 100 years (Kagetora's summoning) and Kotone was summoned after 100 years Kagetora was summoned (which makes it 200 years since Haru went missing)
i hope I explained it clearly
Timeline is so confusing.... are even idols already existed 200 yrs ago?
But the recent servant was MC but tortoise's servant lived long enough to be known by him...
Or unless tiger's servant and tortoise's servant were of the same timeline and 100 yrs has passed since MC's arrival and I just missed it?
Wuuuh???