The Seven Plagues
The Seven Plagues are a race of seven dragonborn, named One, Two, Three, Four, Five, Six, and Seven who were created during or after Godfall when their father, the god of all dragons, perished. Led by One, they began a long campaign of destruction on Golarion that was halted when Seven abandoned the group and their mission.
Sortan met Seven shortly afterwards. The two warriors clashed with the other Dragonborn on several occasions before they came to the Federation.
The Federation Lords met Six and learned that he had also abandoned One’s command. Six helped them obtain the Dragon Orb of Acid but later fled when he felt he could not resist One’s mental commands.
The Plagues gathered on the Isle of the Dreaming Jungle to assist the First Plague, One, with his ritual to resurrect the dragon god. During the ritual, Six was slain by lizardmen sorcerers, who sacrificed the dragonborn to empower One, while Four was slain by Sortan as the Federation Lords attempted to stop said ritual.