Another webtoon or sum ive read before that i want to find

Where the mc playing a mobile game, and slowly raised them up, until one day he was summoned inside the game, not on his own account, but another persons, and they level up
And the characters on mcs acc try to find mc because he suddenly disappears (i remember reading that mc was able to go into his account for a bit because of a portal or something and he met the characters he raised)
Also theres this room where you can throw a few characters in with the one you want to rank up, and the strongest comes out stronger, while the others become level up things for them
Also, if a character dies then they never come back i think

Pls help ☹☹