From ROI Wiki

The Guardians are a specialized group of combat soldiers built by Dr. Slao to combat the growing threat of the Margog and his Horde army. It's leader is Rom and its executive officer is Sine. However, when Sine is killed defeating the Margog, Sine takes over command of it and its few remaining members. Eventually he becomes the last living guardian and continues fighting for the Yigzan people, alongside Tgegani, and his two companions Ver-mach and Ick-pok until the fall of Braisail where he, Tgegani, Tiel, and his two companions all willing surrender their lives, having reached the end of their journey, and the end of the work that Meshua created and sent them forth to complete.