The Tax-Dodging Teen's Pirate Adventure

The tax-dodging boy, Kirei Kotomine, who fell on the road to achieving his goal, accidentally reincarnates in the world of pirates and is adopted by a priest named Alexander Anderson. Thus begins the tax-dodging boy's journey through the pirate world.

(There are quite a few original settings in this story. Please be understanding if anything is inaccurate.)

He will be in the Navy during the early part of the story, and become more and more delighted later on.

The story takes place roughly twenty years before the events of the anime.