Tauru is Soruen's father, and a father figure to Prince Rimudo alias Uruki. He is a loyal man and a skilled warrior.
When he was asked by Uruki's mother Ayula to protect a baby Rimudo from Temudan, he loyally agreed and vowed to keep the child’s true identity a secret until the time was right.
For several years, Tauru was on the run with a little Uruki and a teenaged Soruen, training and protecting both boys. Eventually, however, the military caught up to him and he was killed, and so the responsibility to guard the crown prince was passed on to Soruen.
Rimudo, who was a little kid at that time, blamed himself for Tauru's death, and attempted to kill himself over it. Soruen was also very upset but found it in himself to forgive, save, and continue being Rimudo's Guardian, training him and taking care of him loyally.