MTL - Start with Batman - Chapter 196 air ghost

This is a world shrouded in darkness.The spreading Black Fog corrodes every living creature.The only protection for humanity lies in fire.But as the dark Epoch approached, the fires slowly extinguished.Countless strong Kingdoms became dens for Dark Monsters, humans lost contact with each other, and survivors trembled in the faint solitary light.Until Rod came to this world.“Damn, what's this cow and horse stuff, is it edible?”“This Soul, it's delicious.”“As long as the will of fire remains unextinguished, I believe, one day, humanity will once again illuminate this world and burn all spectral vermin to ashes.”“Even if I'm mired in darkness, bearing the Dream Realm, I can still support this world!”“We've won!”——The world is about to fall, the Abyss looms at our side.And I will raise this Unique flame to light up the world.Yes, I am the last King of Darkness.But...Hello? Anyone, save me.

All Things of this World, Turn to Ashes, Flowing Blade-like Flame!

Crossing over to the world of pirates(the one piece world) , in the era of pirates, the Roja from eleven years ago obtained a Sword Soul system that lets him strengthen infinitely and extract various kinds of skills.

Flowing Blade-like Flame (Ryūjin Jakka) , Mirror Flower, Water Moon (Kyoka Suigetsu), Moon Fang Heaven-Piercer (Getsuga Tensho), Thousand Cherry Blossoms (Senbonzakura)……

“If this sword descend, you may be roasted to death.” Roja looked at Akainu in front of him and seriously said.

- Description from novelupdates

Just like how everyone adored heroes in their childhood, a certain young man adored those powers hidden in shadows. After hiding his strength and living the mediocre life of a mob character by day while undergoing frenzied training by night, he finally reincarnates into a different world and gains ultimate power. The young man who is only playing at being a power in the shadows, his misunderstanding subordinates, and a giant organization in the shadows that gets trampled…. This is the story of a young boy who had adored powers in shadows possibly eventually reigning over the world of shadows in another world.