The Star of Steel! Subaru, Embrace your Fighting Spirit of Steel! - S1.E60

The Steel Saints training facility is stormed by the Pallasites led by Hati. Koga and Subaru arrive soon after and they learn that the residents had previously evacuated with former Bronze Saints Ban and Nachi. While investigating, Koga learns about Subaru's origins from his fellow Steel Saint Erna, and it is revealed that among the Steel Saints, Subaru has the strongest Cosmo, and that one day he may find his own Guardian Constelation and become a proper Saint.