Kougai Koufuku  

Sai, 黄蓋 公覆/祭

In Shin Koihime Musō's sequel, there is a new character who infiltrates Sōsō forces during a major naval battle (referring to the Chi Bis Battle) under the guise of defection. This cunning warrior sets Gi faction ships on fire and ultimately leads to Kazuto joining the Gi Faction. However, Kōgai is eventually killed for these actions.