Akuyaku Reijou ni Nanka Narimasen. Watashi wa『Futsuu』no Koushaku Reijou desu! - Chapter 134.1: Best friend and request.

[Warning! The MC here is the literal incarnation of evil and madness throughout the story.]Valtar Titanblood formerly known as Ethan Martin on Earth was struck by an unimaginable tragedy and took his own life at the end, his whole life filled with misery and incompetence of his own doing.Then he transmigrates to a world of infinite proportions and power that defies logic, this new world which is filled with Dragons, Titans, Ouroboros, and countless more bloodline creatures and mythical beings, also powerful humans who are known as Mystic roams here as well.Valtar in this new world has the Karma System and the bloodline of an unknown titan running through his veins, with these powers in hand he who was supposed to become the symbol of justice and equality decided to become the paragon of madness and evil.He who had the tools to become the Judge of Truth and the figure of Respect chose to become the arbiter of chaos and the embodiment of fear.

Xia Yan passed through to the world of Bleach and became an eleven-year-old boy. He was rescued by Renji and Rukia in the Seireitei, and he was studying at Shin’ō Academy, and he was a student of the same class.
He is a top student of the Shin’ō Academy, and he is vying for strength by various teams. In the end, he has entered the first team of secret mobile maneuvers.
He will use punishment to kill every person who tries to threaten the martyrdom and protect his loved one.

- Description from Novelupdates

Guan Dounan traveled to the world of Conan, and unexpectedly found that he had a stand-in “King of Comedy” and became a stand-in messenger. However, this double actually looks exactly the same as that “little black”?

As the so-called stand-in messenger will attract each other, Conan is the stand-in messenger, Xiao Ai is the stand-in messenger, Kidd is the stand-in messenger, Xiao Lan… Oh, she doesn’t have a stand-in, but she has double A.

In addition to this, there are many stand-in messengers who choose to embark on the path of crime, and it is time to count their sins.

“Little guy, your ability is the most useless!”

“I understand, the ability of gin! It’s…”

“Yahahahah, it’s a stand-in of the same type as my comedy king.”

“Senior Guan! Hurry up and think of a way to use your invincible stand-in!”

“I Guan Dounan just want to live a peaceful life…”

(Original stand-in, based on the world view of Conan, the characters in jojo will occasionally make cameos)

(On the basis of the original case, the magic change is not limited to the pure stand-in ability, but also has supernatural, demon, and superpower elements. In short, it is metaphysics to the end.)

(Slow heat, although it sounds weird to say this, but in the early stage, I mainly laid various foreshadowings, so it will look a little dull)

- Description from novelbuddy

I am Master Siwei, and I speak for arcane arts.
This is an era of heroes and heroines.
This is an era of great changes.
In the end, it will be an arcane era opened by me.

- Description from Novelupdates