Guild Mage: Apprentice - Chapter 96. Time and Tide

Gawain is dead and was transmigrated, but there was a slight problem during the process.
After floating for more than a hundred thousand years on a different continent, he felt that he might need a body to become a complete transmigrator, but he did not expect that…

- Description from Novelupdates

A demon phoenix cultivator died in the hands of his beloved and was merged with a young master with the same name. Their souls were fused and now, the new Feng Fei Yun is struggling to become stronger and survive in the human world.

Warning contains-Incest/Ntr/ Heavy NetorareA Boy struggles with the problems of being raised in a family full of lewd older women.

A girl who calls herself a demon appeared before a timid student named Fumio Kijima. The girl claims to be a campaign girl from the demon world and she gives him the ability to “summon a room” from nothing but thin air.

At first he doesn’t abuse his power and uses it as a convenient ability in his every day life. But one day he is bullied by his classmates under a false pretext and is made to suffer. In the past he would have wallowed in misery and cried himself to sleep, but now he had a power to call upon.

“I will make them regret it!”

Using his powers to summon his “room”, he begins his era of confinement and brainwashing to achieve his goals.