A young wimpy boy got a Yo-kai watch at 10 y/o, befriending Smogella, Tyrone(a black cat yokai from the Shady tribe, also a yokai watch hero compatible yokai, shadow powers), and Jasmine(calico cat yokai(more actual cat like then most, think puss in boots type bipedal), charming tribe, YWH compatible, electric powers).

At 13 he obtained the Yo-kai watch Hero, allowing him to become a Yo-kai Hero with the help of either Tyrone(becoming Strike Kuro) or Jasmine(Spark Star(pun on Rock star))

Yo-kai(yokai watch) and Yokai(highschool dxd) are different and the same, Yo-kai come from the yokai world, while Yokai are from earth, an update in the yo-kai watch has allowed yokai to be able to be called with the Yo-kai watch.

He also has a Subspecies Twice Critical, Shadow Gear(allows weaponozation of shadows) as well as the Holy Sword Clarent

At 16(age of the main cast) he's still a wimpy teen, but in secret he's a yo-kai hero helping with yo-kai troubles.