Wapeach is a scraped villainous version of peach akin to Wario and waluigi. This is my personal interpretation of what she would be like.

Wapeach is a fucking wabitch. She's selfish, rude, greedy, egotistical, spoiled, hot-headed, and especially loves to kick downwards.

The only two people she gives a shit about is Wario and Waluigi, whom she often (tries) to take a leadership roll. She also hates peach, and has a rivalry with her. She also might kick you like a football, so watch out.