SpiderGwen: I have a system?! - Chapter 87 - : After the Darkseid War I

A chance to change, to challenge destiny, making dreams a reality, and live a legend! A regular man gains a system that allows him to turn into a fish!

- Description from Novelupdates

Cassian Ven Dyke, the bastard son of a powerful ducal family, grew up in the slums of Veldora under the care of his father figure, sword master Russel. When Russel passed away, Cassian was left with only a silver necklace as his inheritance. After putting it on, Cassian was attacked by three psychotic thugs who tortured him in an attempt to steal the necklace. Refusing to give in, Cassian was ultimately stabbed through the heart with the very same necklace. Instead of dying, he mysteriously vanished as the necklace lodged itself in his heart. Just before disappearing, he heard an eerie message echo in his mind:[True mana detected. Origin: Human...][Human detected. Compatibility with system: Confirmed.]

The teenager Long Ao, ten years of silence, was reduced from genius to waste, and was ridiculed and mocked.

Ten years of persistence, ten thousand failures, and finally won mysterious Dragon Seal.

With Primal Chaos Saint Body, cultivation invincible cultivation technique, refining Heaven and Earth, devouring endless stars, sweeping the wasteland! Ask the vast stars, who dares to fight me? Boundless Starry Sky, War God! …

- Description from Uukanshu

One week. If you survive, you choose a Cosmic Power... you survive. Jace isn’t one to give up. Not when his sister dies. Not when he loses his legs. And definitely not when The Cosmic System takes over Earth. With nothing more than his street smarts, the clothes on his back, and a river otter companion; he must survive a planet full of vicious predators that see him as an easy meal. If he can survive? He gets to choose a Cosmic Power and a Class. A path to ascension. A way to bring his sister back.