Waber

A young man living on the GUARDIANS Colony. While attending a celebration commemorating the centennial of the Tripartite Treaty, he and his sister Lumia are caught in a SEED attack. After this experience, Ethan joins the interplanetary security force, the GUARDIANS, and begins training under Karen Erra.
Ethan Waber, the main character, and his little sister Lumia Waber, are at the celebration of the 100th year anniversary of the Alliance Space Fleet on the GUARDIANS Space station. The celebration is interrupted when a mysterious meteor shower almost destroys the entire fleet. During evacuation, Ethan and Lumia split off of the main evacuation route, and collapsing rubble separates Lumia from Ethan. Ethan then meets up with a GUARDIAN named Leo, but they are attacked by a strange creature. The creature paralyzes Leo, and Ethan takes his handgun and kills the creature. Leo then tells Ethan to find his sister, and that a rescue team is on the way.
After killing multiple creatures and saving people, Ethan finds Lumia, and they both leave the station. After a conversation between Leo and Ethan, Ethan reveals that he dislikes GUARDIANS because his father died when on a mission. Leo, impressed with Ethan's abilities, convinces Ethan to join the GUARDIANS.
Ethan and his classmate Hyuga are trained by a female Guardian named Karen, who leads them against the SEED, the strange monsters that came from the meteors. After being hired to accompany a scientist to a Relic site of an ancient, long-dead civilization, they find out the SEED are attracted to a power source (A-photons) the ancients used and that the solar system has just re-discovered.
Karen finds out she is the sister of the Divine Maiden (the prophet of the Holy Light) and takes over that position when her sister dies at the hands of her estranged father who intended to kill Karen to increase the original Maiden (Mirei)'s power.
After befriending rogues, guardians, and casts alike, Ethan angers Magashi, a CAST who heads the Endrum Collective and has been kidnapping scientists who know about the ancient power source. After Ethan and a rogue named Alfort Tylor kill Magashi, Ethan helps activate an ancient weapon the prior civilization used to survive the SEED before they were almost completely wiped out.
Ethan then gathers allies against Guardian orders to attack the last SEED outpost standing where two of his friends and the scientists are being held. In the outpost Magashi claims to be brought back to life by the SEED, where in reality he is a CAST incarnation of Dark Force who controls the SEED itself and controls whatever they infect.
With the help of Karen, Leo and Tonnio, Ethan defeats Magashi once and for all.