Ryjaan was a Danteri man in the 24th century, an ambassador of the Danteri Empire. He was the son of Falkar. He had a squat and bulky build.
Ryjaan collaborated with Yoz, D'ndai and Zoran Si Verdin to forge a coalition of Thallon, Danter and Xenex that might ascend to rival the Federation. (NF novel: End Game)
In 2373, Ryjaan attended the meeting on the USS Enterprise-E to discuss the future of Sector 221-G after the recent fall of the Thallonian Empire. Before the meeting began, he denied Si Cwan's accusations that the Danteri had aided in the empire's fall, then attacked him when he called him a liar. During the meeting, he opposed direct Federation involvement and was informed by Admiral Alynna Nechayev that the Federation would not allow Danteri ships to enter the sector. He learned that the USS Excalibur would be sent in to offer assistance and humanitarian aid to the sector's inhabitants. (NF novel: House of Cards)
Ryjaan returned to Danter and met with D'ndai of Calhoun in his office. He expressed concern that Mackenzie Calhoun, who had been assigned command of the Excalibur, would interfere with their own plans for the sector. Ryjaan demanded that D'ndai do something to impede Calhoun's efforts, warning him that otherwise he would have to take the matter into his own hands. (NF novel: Into the Void)
After an attempt to lure Calhoun into a trap instead resulted in the capture of Si Cwan and Zak Kebron, Ryjaan met with Yoz, D'ndai and Zoran on Thallon to discuss what to do with the former prince. D'ndai rejected the idea of killing him outright and instead advised putting him on trial for aiding the Xenexian rebellion, lying to Ryjaan that Si Cwan killed Ryjaan's father Falkar. However, when the trial was held and Ryjaan accused Si Cwan of this, Calhoun revealed that his brother had lied: it was not Si Cwan that killed Falkar, it was him. Enraged, Ryjaan invoked Final Challenge against Calhoun, which he accepted. The fight, held in the mountains, was interrupted by earthquakes which caused the land to sink into lava. While dangling from a precipice, Ryjaan refused Calhoun's offer to save him and fell to his death. (NF novel: End Game)