The Overlord of Blood and Iron (WN) - Chapter 300

Alex, a veteran soldier, meets an unexpected end on the battlefield. But instead of the final rest, he finds himself reborn into a new world—the magical realm of Harry Potter. Now a young boy, Alex is born into a Muggle family. Yet, despite his non-magical origins, his disciplined training and fierce determination uncover a rare, powerful talent for magic. With a world of spells, wands, and ancient secrets ahead of him, Alex will need every bit of his skill to face the growing darkness led by Voldemort. It’s a time before Harry Potter’s birth; James and Lily Potter are still alive. Join Alex’s journey as he navigates his way through Hogwarts, learns the mysteries of magic, and rises to face the deadly challenges that await, determined to become one of the greatest wizards in history.

I became the childhood friend of the protagonist in a novel. The childhood friend who died from taking drugs.

There was once a hero.

Unique black hair. Excellent eyes. Contrary to his delicate features, he who had abnormal strength was called the Otherworldy Hero.

At the hero’s long adventure (up to the point where his wooden sword that had been kindly granted to him by the king was replaced by the holy sword blessed by the holy maiden) he saved the prince that had been kidnapped by the demon king, and so the kingdom was swept by worry.

The hero’s strength that could fell the demon king was deemed too dangerous to leave unrestrained.

One advisor spoke up. Why not marry him to royalty?

The king thought that was a viable option. Family, to an alien from another world would be the best of chains. There was one problem. The king was abundantly blessed with sons and had princes galore, but not a single daughter.

Ho, and it wasn’t like I could marry off two boys.

At a burst of inspiration the king slapped his knee.

That was it!

You just had to turn a prince into a princess!

And so the hero ended up in a position to be marrying a man.

This story, is a tale of the aforementioned otherworldly hero, and his bride, the former-prince-now-princess and their ridiculously hilarious marriage.

After Reincarnating into Naruto World at the Warring State Era as an Uzumaki, Masahiko thought that he got a useless System. He lived for 48 years as a normal, below average Uzumaki Shinobi.

That changed when he finally knew how the system works the day of his 49th Birthday!

- Description from Novelupdates