[Invincible + apocalypse + cultivating immortality + supernatural powers + no heroine] Cultivate technological immortal arts, forge a nuclear-fusion Golden Core, and remain immortal throughout the endless universe!
What? This is a technological apocalypse, where technology runs rampant and morality has collapsed!
No spiritual energy? I’ll cultivate nuclear energy. No spirit beasts? I’ll butcher mutated beasts... Supernatural powers are my blood, biochemistry my bones, and machinery my tools. Everything is cultivation fuel to help me attain immortality!