MTL - I, The Grandson of Garp, Scared Luffy Into Tears - Chapter 615

Gao Yang was an orphan who, at the age of six, crossed over to a “parallel world” and began living in a warm family of five.When he turned eighteen, Gao Yang accidentally discovered the truth about this world: it wasn't a parallel world at all, but a mysterious realm, and the loved ones and friends around him were all terrifying “Monsters”!Gao Yang, upon uncovering this truth, narrowly escaped death and, at a crucial moment, gained a system called “Luck” .The longer he survived, the stronger he became! And so, a deadly game of sheep and wolves unfolded...

[Ding, your frog was afraid of your death, so he went on a trip overnight and stole a shelter for you! 】

…

Reborn into a world of global catastrophe apocalypse.

In the face of global recovery, zombies, fog, meteorites, prehistoric creatures, glaciers, earthquakes, acid rain and other devastating global disasters, the only thing Ye Su has to do is to survive.

Unexpectedly, he got a traveling frog when he arrived. The frog was afraid of Ye Su’s death, so he simply stole a shelter!

Ye Su: “???”

But what’s even more outrageous is yet to come.

[Ding, your frog is afraid that you are not stable enough, so he stole the source of fire for you]

[Ding, your frog was afraid that you would be bitten, so he stole the antiviral potion overnight! 】

[Ding, your frog stole the Zanpakutō for you! Additional Asura – Blade Skill! 】

So, when everyone was avoiding zombies, disasters, despairing for food and water, Ye Su had already carried a big knife, drove a car, and came out for food!

- Description from novelbuddy

When crossing over to multiple books, Ren Shuhan found that every protagonist Shou was waiting for him to start chasing them in the crematorium.

“Don’t waste your time waiting,” He advised sincerely, “There are more 0s than 1s, so I’m not going to chase someone that is not interested.”

The protagonist Shou (sneering): Oh, there will be a day where you’ll lick the ground I walk on.

After waiting and waiting…

Ren Shuhan: “This is the wedding invitation for my childhood friend and I’s wedding.”

On the wedding night, Ren Shuhan removed the veil: “Baby, I’ve come to marry you.”

“Don’t you know that life is nothing but a play where you are the male lead and I am just a supporting character?”

“I know, but I don’t care.”

He was smiling, but Jiang Qingyue wept.

- Description from Novelupdates

The strongest Demon Lord dies, and reincarnates as a human. Not only that, he because of various incidents turns into the hero’s best friend.

Follow his journey as he tries to help the hero escape his fate, and on the sideline to conquer the continent while he’s at it.