Malaria was a gothic woman who fell in love with Grim in Grim In Love, which was also her only appearance.
She shared Grim's sadistic sense of humor and loved to hang out in graveyards, at the end of the episode Grim took her to his favorite bar where he introduced her to his neitherworld friends she then saw his powers, realizing that Grim was actually the Grim Reaper, and that his friends were real monsters, she panicked and ran away she has only been seen in cameos since then.