If you're looking for manga similar to Shadow: Super Human Assistance Department Office Worker, you might like these titles.
In this epic team-up between Iron Man and Spider-Man, Tony Stark travels to Japan to attend a gaming convention. Awaiting his arrival is Reijiro Kaioh, the CEO of a world-famous card game company. Kaioh plans to unveil an amazing new gaming machine, but the inventor and his device are not at all what they appear to be…
Monsters are on the loose! But luckily for the people of Japan, heroes are there to protect them, with powers that run on a rate of yen per second. For Hiasa Sen, however, there are many more important things to worry about, like catching sales on groceries, and his many part-time jobs, all to take care of his little sister. When danger approaches, however, he has a secret power of his own, but it may be more trouble than it's worth.
Since the government announced the existence of people with “special powers” 10 years ago, Shindo Susumu has longed for his own amazing abilities. However, he finds himself to be nothing but an average 15-year-old. Then one day, during his high school entrance ceremony, a power finally awakens inside him…but it’s not exactly the kind he’d always hoped for!
Koichi Haimawari couldn’t make the cut to become an official hero, so he uses his modest Quirk to do good deeds in his spare time. Then one day a fateful encounter with some local thugs leads him to team up with two other unlikely heroes. None of them really know what they’re doing, but they’ve got the courage—or foolishness—to try. But they soon discover fighting evil takes more than just being brave…
After years of frustration, Kim Gidoo is about to have his first time with the girl he loves. But then, he's kidnapped by a group of suspicious people, and learns that he's to become a hero thanks to his super-powered sperm...
Long ago, when danger approached the Earth, there existed people exhibiting their superhuman powers to save the planet; to help the weak; to defeat evil and to promote justice. Earth never hesitated to sacrifice such beings. The powerless set these people apart and honored them by calling them heroes. However...the era somehow changed...