His Warrior (Nine Tails, 4) by Yuki Edo
Kazuma had never failed in battle until the day he let jealousy drive him from his post. While secretly protecting Ichiro from the yakuza, Kazuma had fallen in love, but he’d denied those feelings until the day an assassin found Ichiro and almost killed him. Now, Ichiro is confused and defensive after learning Kazuma has been spying on him for years. Will Kazuma find acceptance and love with Ichiro, or will he be rejected and forced to protect him from afar once more?