Skeleton Knight, in Another World - Chapter 22Volume 8 -

This novel is also known as The Demons Beside Me

Chen Zhao can summon demons and see Death.

“Beelzebub, use your Gluttony ability to treat this patient’s anorexia.”

“Raymond, this old man wants to regain his manly function. You know what I mean.”

- Description from Novelupdates

Lin Wanwan is a pitiful mentally-disabled girl. Not only does she suffer abuse from her stepmother, her stepmother even attempts to use her as a sexual commodity to pleasure others. Eventually, the poor Wanwan dies from an overdose…

An alien race invaded the Earth on June 6, 2128. At the midst of this war, many nations allied with the alien threat and the war nearly wiped out the rebelling humans of the planet. At the edge of mankind's survival, the United Nations Army launched its forces to eliminate the immediate stellar threats that loomed over Earth.

General Seeker Carlean, commander and leader of the mission, risked and gave his life to destroy the immediate stellar threat. The battle was won though Earth lay in ruins. Perhaps mankind will live to see a few years of peace before the alien threat returns to wipe out their existence.

At the immediate aftermath of the stellar battle, the fallen Seeker Carlean awakens and finds himself at aged 17, living the peaceful life he lived 16 years before he died.

So begins a new game in the battle for humanity's survival.