[Prince of Tennis Main Story] Who Is the Female Lead?

She roared, "It was Wang Xiaotian in my last life! And it's her again in this life! Why does she get to have everything, while I get nothing?"

I replied indifferently, "Because you're a goofball."

→_→ This book is also known as...

"□□"

Or...

"Deep Red"

"The Protagonist Is Just Watching"

"The Story of Two Supporting Female Characters"

"The Toxic Supporting Female Character Is a Mary Sue"

→_→