Extremely Brave Aliens: Rebels in the Eternal Era

[World view: 2050, the age of immortality] Humans can achieve permanent self-healing of cells + immortality at the age of eighteen, and disappear after natural death. Death becomes the ultimate choice: each person is given a tube of "aging reagent" at birth and dies peacefully 24 hours after the injection. A unified and peaceful government around the world, sufficient supplies, no war, and extremely comfortable life. Some people devote themselves to planet colonization, Others are unwilling to give up the opportunity to break through themselves and form an open fighting alliance - extremely brave men to face their limits and temper their will. Anti-domestication, anti-routine.