I guess they were created to be the "evil versions" of Mario and Luigi.
I believe so too. Wario was created by Gumpei Yokoi, the creator of the Super Mario Land series. I don't think Waluigi wasn't created by him, because he (Gumpei) died in 1997, and Waluigi appeared in 2000. --KamariU (talk) 02:10, April 10, 2014 (UTC)