Redwater or Ninedust Sectlord.
He was originally a leader of a group who was at odds with Ji Ning, but after encountering an accident where they were sucked into a Black Emperor's body, they became close friends and eventually life and death brothers.
They have helped each other many times and were together for a few chaos cycles, Redwater eventually leaves to gain more insights and not be hindered by having Ning by his side.
As of Book 43 he has not attempted the daomerge, estimating that he will be ready in 10,000 to 50,000 chaos cycles. He has recently attempted the daomerge and was successful. He has become a Hegemon.