Manga about a person who goes into the past

Question

I read this in the past and lost it, the main things I remember are

• Character dies and gets placed into his body from a few years back
• the world was normal but then turned into a game where the players kept their progress
• Character has a sister that he takes care of
• Rejoins the game knowing the secrets and gets mastery 100% on every weapon to unlock "Ki" while the other players think he is stupid for not level grinding
• Is in color

Answer 1

I think it's the It All Starts With Playing Game Seriously where the main character gets sent back in time and there is Ki in it.

One born as an ant out to have will and ambition. Fate has not yet been determined; each of us are a black horse. When the game [Yuan World] descended into reality, players gained the ability of their in-game characters. As such, the world became chaos. Liu Yi — forbearing, ambitious, yet afraid of fighting— time travels to an era before the game had become reality. Armed with the knowledge of the future, starting from the bottom to overcome his fear of fighting, Liu Yi rises up to the top, ultimately becoming the Savior and resolving the crisis of the apocalypse.