Kizuna

From childhood friends (since elementary) to lovers (since high school), Kei and Ranmaru have been through a long road consisting of hardships and fond memories. Now in college, they face a new challenge to their relationship when the son of a Yakuza boss (and incidentally Kei's half-brother), Kai, attempts to steal Ranmaru from Kei (and, of course, fails).
Ranmaru is the best fencer in his school. One day while he and his friend, Enjoji, are walking home from school, Yakuza from a rival syndicate try to run his friend over with their car. Ranmaru pushed his friend out of the way and gets hit instead. This event sparks the romance between Ranmaru and Enjoji. A few years later the relationship between them is still strong until Enjoji's half-brother, Kai, shows up and trys to take Ranmaru away from Enjoji. Then Masa, Kai's companion and mentor, shows up to see Kai.