1000 Yen Hero

Mysterious monsters attack the people of Japan, but heroes are there to protect them with powers that run on a rate of yen per second. For Hiasa Sen however, there are much more important things to worry about, like catching sales on groceries, his many part time jobs and most importantly, taking 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.