My Cheat Skill Lets Me Copy Powers....But only if i kill - Chapter 3: Kill Or Be Killed

A 30-year-old NEET is reincarnated into the body of an otaku that choked to death on instant noodles. As he comes to grips with his new life, he realizes that this world is subtly different from Earth. The denizens of this world are far better looking, and this new world also possesses futuristic technology as well as mysterious Yin Yang masters!

After reincarnating, he realized that he was endowed with a miraculous game-like system, which enables him to increase his own stats and transcend the limits of the human body. This system even has a game-breaking ability to save and load in real life!

In this new world that’s akin to a 2-D game, he just wants to enjoy life and head for a glorious future… However, he is quickly embroiled in a complex plot. Can he unlock his true potential and utilize his system to break the shackles that confine him and discover the truth about his previous body’s circumstances?

- Description from novelupdates

Being given a chance and reincarnated is nice and all, yet why do I have to become that male friend who just watches the protagonist flirting with his harem?---World: Kaguya-sama: Love Is War - Hyouka ----

When the human princess, Lareina is sent as a bride for a peace treaty between the demons and humans, she ends up in a political marriage with the second prince of demons, Prince Azrael. Lareina falls for his gentleness that sets him apart from the rest of the demons in her eyes but on the night of their wedding, he is deployed to the war.Years after his abrupt departure, Azrael has finally emerged victorious and returned. However, much to Lareina's dismay, he has brought back a beautiful demoness with him. At the receiving end of his hatred, a heartbroken Lareina tries to save their marriage until all her hopes are shattered. Determined to carve a way for herself, she decides to end the marriage but she is met with a new challenge when her seemingly uncaring husband suddenly refuses to let her go.

Brolin, the nine emperor of the Black Dragon Mountain Empire, accidentally obtained the system of the realm of the world, and began the legendary journey of the battles!

In the Naruto world, with his star power, he overwhelmed the shadow-level powerhouses, grabbing reincarnation, and becoming a ten-tailed person!

Fighting the mainland, he led a large group of lords, surrounded the ancient eight clan, and confronted the peak Dou Sheng!

Covering the sky, he broke into the restricted area, seized the emperor’s scriptures and immortal medicine, and called the Lord of the human universe to fight supreme, and the sky was falling apart!

In the eternal life world, he crosses all realms, and fights against the Supreme King of Stone with the attitude of eternal true God!

Immortal continent, he jewels Jiuyang, looks down on immortal ancient, strong sky!

The perfect world, he runs across the sea, suppresses the heavens, and the Zhunxian Emperor must retreat!

Thinking of the eternal world, he ascended to the realm of Supreme Hunyuan, the fifth step of the war, Bai Xiaochun!

Heaven and earth, this is an epic of the black dragon!

- Description from uukanshu