MTL - Rebirth Merchant: Wonderful Space Hunting for Military Officer - Chapter 32 revenge

I returned to Earth as the invincible Knight King. But the Gods came with me.

Side story of Kyoukai Senjou no Horizon bundled with the first press release of the 1st, 3rd, 5th and 7th Blu-ray volumes of both seasons of anime.

This side story follows Asama, Kimi and Mitotsudaira aboard Musashi one year before the beginning of the main story, as Asama is considering to create a music band together with her two friends for the next festival in Aki, a territory under the governance of K.P.A. Italia.

When the cosmic tyrant Frieza detonated Planet Vegeta, home of the Saiyan race, a twist of fate sent a lone infant—placed in an escape pod by his mother—hurtling through the void toward an unknown destiny. The pod's trajectory led him to a desolate world: Titan, a planet ravaged by catastrophe and long stripped of life.Beneath the shadowed skies of this barren realm, the watchful eyes of Thanos, the self-appointed director of the universe's population balance, beheld an unexpected sight—a child, the sole survivor of Titan’s forgotten civilization... a child with a tail swaying behind him.“A survivor of Titan... From this day forth, you shall be my son.”

With the revival of spiritual energy and the breakdown of the order of species, it is a difficult test whether human beings can still stand at the top of the biological chain.

(There is already an old book, The Strongest Descends in the City, you can read it.)

- Description from novelbuddy