Abandoned by Everyone, I Became Noah's Human Host

(Multiple female leads + a dark plot, not exactly lighthearted + original story. Some of it is bleak and explores the darkness of human nature. If you like utopias, this might not be for you.)

Chen Feiyu is reborn in a world with Ultraman, but no Land of Light.

Humanity has built its own Plasma Spark Tower, and only a tiny number of people can become Ultraman.

Chen Feiyu becomes Ace's human host alongside his childhood sweetheart.

During one battle, his childhood sweetheart uses her abilities without restraint, draining most of Chen Tianyu's power and nearly causing them to lose. Chen Feiyu grits his teeth and manages to defeat the monster, but after the battle his childhood sweetheart dismisses him as useless and exiles him from their new home planet, leaving him to fend for himself on Earth.

On his way back to Earth, Chen Feiyu encounters the Light of Noa. This Noa has a human-like personality and chooses Chen Feiyu to become Nexus's human host.

Chen Feiyu: