Only one copy and no you can't rank up a monster with the same type and it needs be a rank above and within the same mythology, species or origin. There are also genders, and regional forms some monsters have different form in other countries
I'll spoil as much as I can get for the reason why fatso is mad at maro and how the rest of the tournaments gonna go
Nanzan - Maro
Renka Spoiler
About the Skill: Falling Existence and spoilers for the future chapters
READ AT YOUR OWN RISK!!!! THIS IS ONE OF THE REASON I GOT HOOKED ON THE...
Iirc the pronunciation is ME-AH but it was Romanize MARE I'm thinking of asking Hyakuen on twitter but he's busy shit posting.
Btw if you like the series pls support him and Sagiyama-sensei on ComicNova and Kakuyomu
Hyakuen recently quit his day job so if any of you has spare change pls...
I really want this series to br good because of the art but damn the webnovel is hot garbo. Even though I like hot garbo I still wanna pluck my eyes whenever I read that thing