[Prince of Tennis] One Day, a Mary Sue Showed Up at My Door

Tezuka Rie had spent most of her life in the hospital, and nearly every New Year was spent there.

When she was seventeen, a voice suddenly told her, "You won't live to adulthood."

Just as Rie was sinking into despair, another voice appeared. "Make a deal with me, and I'll help you survive."

And so...

Tezuka Rie became a temp worker in the [Mary Sue Plot Breakdown and Correction Department].

Mary Sues kept showing up at the Tezuka residence, and she had to kick every last one of them out so that their targets wouldn't fall under the spell of their halos.

Premise: I alone am an alliance!