Ryon Dunsly was a young Titan (about 423 years old, which is young for Guardians) and has accomplished so much with the help of his Ghost. (Note: this is where my touches on the story come in) He killed Riskis, the Devil Archon on his first mission as a Guardian and fought with the House of Kings in order to cripple the House of Devils. Though in truth the Kings were trying to stop the Devils from rising against them ( the Kings ruled them from their puppet Kell-Agrus) by killing Sepiks Prime, though the partner ship was tempoaury . A more permanent alliance would be made on the Moon with the House of Exile. This house abandoned Fallen tradition and the will a Kell , which made it easier to negotiate with them.
On Venus, Ryon learned of the Black Garden from the Exo Stranger, took over the House of Winter by killing their Kell Drakis, and stopped the Vex from terraforming the planet.
On Mars, he killed most of the Cabal hiarrchy and destroyed the Heart of the Black Garden, thus saving Earth and the System.
Just a few month's later, the Hive begun a crusade of destruction on Earth and on the Moon (theDark Below). But with the help of Eris Morn, Ryon and the other Guardians were adle to defeat the Hive and their generals.
But only by defeating Crota in his nether realm (Crotas End Raid) would Earth be safe. Ryon used Crotas own sword to slay him.
Now, the Vanguard has detected a strong Vex signal coming from another galaxy. The signal was similar to the Nexsus Mind. Zavala wanted to know if a new Vex threat was coming to the Sol System, they sent Ryon to investigate, using a prototype warp drive recovered from a research lad on the Moon. It was only good for one jump, so he would need to find another way back when the mission was done.