|Abilities||Shardholder, Surgebinding (assumed)|
The Way of Kings (referred to), |
Words of Radiance (referred to),
Oathbringer (referred to)
Tanavast was the Shardholder of the Shard of Adonalsium, Honor. He is/was a deity, widely worshipped on the world of Roshar. His power stemmed from Honor, which presumably fuels the ten Surges. He was killed, or Splintered, by the Shard Odium sometime after the Oathpact was broken, which was a very long time ago.
Whether this was Tanavast's design or not, millennia have passed without Rayse taking the life of another of the sixteen.