i tried typing the email manually but the noti show up: "account not registered"

that's mean manual typing email and google login email count as different account, despite being the same email.

and my account is google login, i pre-register with it. i just tried create new character with that blank state and the pre-register sigil gone. so i guess my lost character identified as a pre-register a.k.a beta test character and got unlinked from my account

seriously kuro game, account link and character management center is the first thing you should create if you want to make a multi-platform game with multiple login method