Delta: the Flicker of Obsidian

[Delta background worldview, non-brainless cool novel, no heroine, no system] Lin Xiao, a retired GTI special forces sniper, had to accept a mission from the old organization because his sister disappeared. However, as his understanding deepened, Lin Xiao discovered that there were more unknown secrets behind it? Relink brain-computer experiment, various experimental subjects in Tidal Prison, the truth about the death of King Ashara... Lin Xiao discovered that he was inadvertently involved in the game between GTI, Hafke and Asara. The secrets he came into contact with could even have the power to change the world.