Triangle Heart: Sweet Songs Forever
Genres: Adventure, Romance
Type: OVA, Episodes: 4
Aired: Jul 24, 2003 to Dec 26, 2003
Studio: Seven Arcs
Source: Visual novel
Rating: R - 17+ (violence & profanity)
Synopsis:
Fiasse is a world-renowned singer. She is now the headmistress of a special Singing School who does a Charity World Tour every year. Her mother left behind a inheritance for her after she died and some shady people are after Fiasse and the inheritance. Bring in Ellis, and two siblings who are master of the swords to protect Fiasse. The World Tour is coming up and Fiasse will continue the show. Ellis, Kyoya, Miyuki and company must protect their childhood friend at all costs. 

(Source: ANN)