Hear My Heart: My World Falls into the River of Love - Chapter 39 — In the future, he will build the largest general merchandise department store in A City.

Kai was a 17-year-old dropout. A NEET. A background character in real life with nothing to his name but bitterness, novels, and guilt. After his parents died, he gave up on the world. People were fake. Dreams were pointless. And that one novel he kept reading? He hated it especially the main character, June. Perfect, noble, always standing tall. Everything Kai wasn’t.Then, one night, a voice asked: “What if you did meet June?”He said yes, half-asleep and half-mocking.Now he’s trapped in the novel. Isikeid. But he’s not June. He’s not a hero. He’s not even in the main cast.He’s an extra in the background of a world he knows too well and he’s had enough of watching things play out the same way. This time, he’s going to change everything. Whether the world likes it or not.

Ronan was just another overworked office drone until a sudden death transported him to a vast, unfamiliar fantasy world—alone, invincible, and armed with absurdly powerful abilities from a game he once played. But reality isn't as simple as a game, and after days of wandering the unending Nim Forest without finding civilization, his optimism begins to fade.Just as isolation threatens to wear him down, he encounters Frieren, a quiet elf girl hiding in the bushes. Their meeting marks the first step on a path neither of them fully understands, in a world that seems empty, yet full of mystery.

“Obtaining the topmost degree of talent in sword arts in the world requires giving up 72 years of lifespan, which leaves you with only five more years of your life. At the same time, you will never be able to feel love, kinship, and friendship, and you’ll end up leading a lonely life until your death, unable to procreate, or to have any descendants.

“From now onwards, everything related to happiness in the human world shall no longer be of your concern. Are you willing to accept this?”

“Hahahaha, I’m already alone bereft of all support, my hopes dashed to pieces, shouldering only absolutely irreconcilable grudge and hatred, why would I disagree? Why would I not want it? I couldn’t ask for anything better!!”

His sword sweeps across the Divine Continent for seven days and nights, moving 90,000 miles through the starry skies, unhindered.

He slays saints and buddhas in Heaven, slaughters demons and devils in Hell, sweeping away all the grievances in his heart!

- Description from Novelupdates

A man reincarnates in the body of a boy who suffered a tragedy, only to realize that he is in the world of My Hero Academia. What's even stranger is that his quirk seems to have the abilities of Nen and Haki.