MTL - Never Marry a Man With Two Tintins - Chapter 15

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

A man is reborn into the world of Avatar: The Last Air Bender as a waterbender from Katara's tribe. Best of all, he was the same age as her, and he had a system with him to help.He knows the future and a system that lets him continuously get stronger by completing quests or long-term missions, as well as giving him the ability to copy abilities from others for himself. He will become invincible in the world of Avatar, even more so than the Avatar himself.

A heaven-defying ring that allows objects to be brought back from games into reality!

In this world, human are in peril. 72 Obelisks suddenly appeared out of nowhere, infecting the world with Monsters. Amongst this chaos, people look for hope.

A man named Basil Pacifer is the humanity's hope. He is the strongest Mage alive at that point. Sadly, he believes in no man, and he always moves alone.

...

Basil observes the unfolding scene bitterly. He is aware of his impending doom, however he has no grudge. He has lived long enough to achieve things people can only dream about.

Looking back to his past, he realized his life is nothing more than a sad story.

Closing his eyes, he accepted his end — or so he thought.

...

”Look at me! What do you see?“

”Regrets.“

”Don't you want to undo it?“

”Tell me what the offer is.“

Thus, Basil Pacifer returned to the past, being his younger self once again. Of course, he returned back with something.

...

[Ding!]

[Guide to Omniscience is successfully merged with The Chosen One]

[Analyzing The Chosen One's mental capability...]

[Analyzation Complete!]

[Result: The Chosen One is retarded]

[Initiate Brain Configuration!]

No matter how useless the golden finger he received seems, he will reach a higher height than his last life. This time, he will completely erase any regrets he has!