Masamune-kun no Revenge
政宗くんのリベンジ
As an overweight child, Makabe Masamune was mercilessly teased and bullied by one particular girl, Adagaki Aki. Determined to one day exact his revenge upon her, Makabe begins a rigorous regimen of self-improvement and personal transformation.
Years later, Masamune re-emerges as a new man. Handsome, popular, with perfect grades and good at sports, Masamune-kun transfers to Aki's school, and is unrecognizable to her. Now, Masamune-kun is ready to confront the girl who bullied him so many years ago and humiliate her at last. But will revenge be as sweet as he thought?
(Source: Seven Seas)
Included Side Chapters:
Chapter 9.5: Investigative Report into Aki Adagaki
Chapter 12.5: A Fine Tradition of Stewardship
Chapter 14.5: Tsunade Island Incident Part 2
Chapter 20.5: Kojuurou Wants To Become A Dandy
Chapter 35.2: Piggy's Memorial Part 2