Resonance: May it Reverberate Forever

Members of the Dragonaut team attempt to protect as many humans as they can from the billions of Ostrums sent by Thanatos. Meanwhile, Toa, Jin, and Gio try to approach Thanatos since Jin wants to persuade it to stop. Kasuga helps them get through by blowing himself up, taking out massive amounts of dragons in the group's way.

Synopsis excerpt via Kitsu.