New Dragon, Elma! (She's Finally Appearing, Huh?) - S1.E8

Kobayashi and Tohru challenge each other to a cook-off to decide who will make a lunchbox for Kanna's field trip, with Tohru ultimately getting disqualified for using an otherworldly fruit for dessert. Later that night, Tohru's rival from an opposing faction, Elma, comes to try and force Tohru to return home, but Tohru puts an abrupt end to their battle. Unable to return to her world, Elma begins working under Kobayashi at her company, prompting some jealousy from Tohru.