Reincarnated as Parasitic Tentacle - Chapter 6: Tentacle Unleashed! (18+)

Seven years ago, she freely and easily abandoned ￥100 and ran away, carrying her unborn son with her. Seven years later, she returned with the lady killer’s genius son, never expecting that her darling son would sell her out to MBS International. Unexpectedly, her immediate superior was the Mr. ￥100 from seven years ago!

Houjou Yuuji, 30 years old, jobless, hikkomori for 10 years. Using his parents’ death as the impetus, he decides to rid himself of his hikkomori life and leaves the house. What awaited him, however, was a different world that he was not used to, creatures strutting about that he didn’t recognize.

This is the story of a man transported to the another world, as he lives in relative peace with his beloved dog Kotarou – his house, with electricity, water, gas, and the internet somehow still connected.

One day while exploring the forest near his house he finds a girl named Alice, and becomes her guardian. Thus, 4 years after he is transported to this world, Yuuji resolves to venture into his first town.

There was once an immortal cultivator fighting for the fate of human beings. Unfortunately, he failed that time; but fortunately got another chance as he was reborn once more as a human, on the earth of 5,000 years ago. With a second chance, he not only would embark on the road of saving all mankind, but also would retrieve his human nature on the new journey that would last for 5,000 years.

- Description from Novelupdates