Tonbo Toryu

Dark Oracle
The first Dark Oracle of Void was Tonbo Toryu, who took up the post in an attempt to balance the elements after the Oracle of Void Isawa Kaede took the throne upon the death of her husband Toturi.

Fortress of Thunder
When the Oracles of Light got together to create the Elemental Nemuranai the position of Oracle of Thunder was unfilled. In a move that surprised even the Celestial Heavens the former Oracle of Thunder and current Dark Oracle of Void Tonbo Toryu demanded the right to contribute his blessing. For his previous sacrifices he was granted the right. The resulting nemuranai was the Fortress of Thunder. (4W pp. 153-154)