Todomomo

Rei: she has a rivalry with Osoro. It's mainly because of Mizumi. He felt sorry for friendzoning her and tried to be her friend again but Rei isn't up for it.

August has a rivalry with Eve for Momo's attention.

Haruhi and Hino have a rivalry with each other

Eve has a rivalry with the world and she's winning.

Kirimina

Akane has a friendly rivalry with Tameiko.

Iro has a rivalry with Osoro because Osoro almost blinded him by accident.

Miruhawks

We know who it is. Rosalind.

Iidamei

She has one with Akane and Stormi

Kamijirou

Stormi has one with literally everyone.

Riitsu doesn't have one

Dabi x Toga

Roman and Rosalind. They're love interests and rivals at the same time. It's like a version of Bakudeku except they're actually best friends and no one has anger issues.

Nejitama

Amai has a very violent rivalry with Megami. Like, a very violent one, Meg is constantly twenty seconds from choking Amai out.

Phoenix has a unspoken rivalry with Manami. Only because he can clearly see that Manami is gonna end up happy while there's him and Daenerys. He's gonna end up heartbroken again. He's jealous of her.

Mt.Kamui

Okuri has a rivalry with Dove. Both are fashion designers.

Ryushot

Megami has one with Amai and Spencer even tho she doesn't wanna hurt Spencer.

Daenerys has a rivalry with Manami as well. Manami just watched her kiss August during a game and got pissed.

HitoRei

Rosalind is gonna fight Dove one of these days. No she won't. She knows that she deserves Roman but hates to admit that dove and Roman are perfect.

Tetsukendou

No one

SetSero

None

Shintati

Riven: Manami

Manami: literally anyone who has tits and talks to August.

Fatjoke

Spencer has one against Megami because of their Sports Festival.

Midotsu

Mizumi: no one

Mariposa: Manami

Clover: no one

Kacchako

Osoro: Rei

Okimi: The bitch from Girl Scouts trying to be the leader