IS: Infinite Stratos EP4 - Showdown! The Class League Match!

Ichika and Lingyin battle in the Inter-Class IS Tournament but their match is interrupted when a mysterious IS attacks the arena. As Ichika and Lingyin hold off the IS so the audience can escape, they soon realize the IS is an unmanned drone due to it's machine-like behavior. Together with Cecilia, the three of them manage to defeat the IS but not before it injures Ichika. As Ichika recovers while Lingyin watches over him, Ichika wonders the promise he made with Lingyin had a different meaning which the latter quickly denies. Meanwhile, Chifuyu and Maya examines the defeated IS and confirms it is an unmanned IS drone with a unique IS Core that didn't come from the 467 confirmed Cores the world has which makes them question who made it.