Magic's Return: I Can See The Spirits - Chapter 3 Who are you?

Once all people received Souls and incredible powers. Some were lucky enough to obtain the Soul of an ancient and powerful creature, but fate was not favorable to all.

The world began to change, and creatures evolved. But, it was not the beginning of a new era. It was the end. A couple of months later, a dark mist appeared and destroyed the world. It was a dictate of destiny from which no one could escape.

Wain Norheim was the world's best assassin and the only one who didn't get a soul. However, he was destined to gain the power to confront fate.

Escaping through a portal into another world, he unknowingly began the apocalypse. Even the world failed to expel him.

Protagonist travels between different anime worlds to right wrongs and uncover his reason for being along the way.

- Description from Novelupdates

A cataclysmic threat looms over all realms in existence, unnoticed by any.The Enigma Race, the harbingers of ruin, corrupts everything in their path, harvesting countless souls for their enigmatic Lord, posing a dire threat to all living beings. No realm is safe.While confronting invading forces from a foreign multiverse, Elias is cast out of his space-time continuum and into the chaotic depths of the Temporal Vortex, a location that has spelled the doom of many, due to a catastrophic accident.To survive, the once supreme Quantum Seeker, now weakened by a cunning invader, musters all his remaining might and, against all odds, transcends the Vortex, losing his body in the process. His consciousness drifted into the miraculous Mystic Multiverse, located in a different space-time continuum. Now, determined to return and save the ones he left behind, Elias vows to reclaim his lost strength.But as time passed, Elias discovered that the new realm isn’t as simple as he initially thought…

With a marriage contract forcefully done, he married her, and all she could do was comply, and resent him deeply for that and for all the following misunderstandings they faced.
However, it was already too late when she understood she actually loved him.