Check in system be like

you walk very sexy to the library of capital city you earn xxx think (ancient inheritance) . Walk more sexy next time . You fall into harem of emperor accidentally . Harem members doesn't give a shit to you because of this you can check in at emperors harem i give you a SSS Class brain-washing-sexy-charm-for-girls use it at harem members and try find some powerfull beautifull protective waifu ( at chinese saying bai fumei i read a lot about them ) :( as a plot armor you can face slap her strong family members too (maybe her father) . Oh noo there is a wild cannon fodder who stronger than you appeared , you succesfully check in at his/her sight to take god level xxx item to kill or if it is a beautiful man/women (change for mc sex ) take for yourself as brainwashed plot armorlike protective hubby/wifey . After very long years later you find You became invincible and no one can beat you and your loved (very very big number) people (they become unbeatable too because of mc's bug) ... you became a god or something stronger than it to use your power for face slap every creature in the universe . . . . . .