The Tiste Liosan are a race found in the Malazan Book of the Fallen. They are not one of the four founding races and only have contact with the Malazan world due to a breach of the barriers surrounding their Warren of Kurald Thyrllan possibly through the human use of Telas, the Path of Fire and the Imass use of the Tellann, the Warren of Fire.
Read more about this topic: Invading Races From The Malazan Book Of The Fallen Series