The HeartStone

Ren Vesper, the outcast son of a traitor, has spent his life in the shadows. When the Aetherials attack and stole the holy Heartstone(the artifact said to be given by Supreme Lord to Humans), the King summons him for one impossible mission: retrieve it from an Aetherial's world(Astora). With a brilliant gunner and a terrified scholar as his only allies, Ren is launched toward an alien world—one-way, no return. But on Astora, he'll discover far more than secrets hidden in ancient stones. He'll uncover a universe vast beyond imagination, where hidden powers awaken within those who survive the unsurvivable, and where the true battle isn't for an artifact—it's for freedom itself.