Nidome no Yuusha - Chapter 128 - The Beginning of the Collapse

Perhaps it is the choice of fate. As a senior otaku, Qian Lingfeng got the “steel shell system”. However, when he swept the world with the system, became a local rich man, made all kinds of beautiful women, opened a harem, and realized the ultimate fantasy of thousands of otaku, he found that things seemed far from simple!
When the end comes, biochemical zombies suddenly come down, fierce beasts are in power, bloodthirsty zerg roam to kill the world, and human lives are comparable to dirt. Where will weak human beings go in this world? Is humanity going to be extinct? Or … can an otaku save the fate of the human race?

- Description from Novelupdates

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

Hanekawa is transmigrated to a body of Kumogakure's spy inside the Konoha and become Tsunade's discipleWill he stay faithful to Konoha, or he ended up betraying Tsunade?

Who says that after rebirth, you have to slap faces, abuse scum, and revolve around enemies and men!Revenge is just incidental! Slapping faces and abusing scum are not the main battlefield of life!After being reborn, of course, you have to live out your own wonderful life, otherwise, it would be a waste of the chance of rebirth.