Raishan

, the Diseased Deceiver, is an ancient green dragon and a member of the Chroma Conclave. As an NPC, Raishan is portrayed by Matthew Mercer.

Background
In, Cerkonos revealed to Keyleth that a young girl named "Raishan" came to Pyrah about four years before the Chroma Conclave attacked Emon. Appearing as a fifteen-year-old human girl, she had great power, but Cerkonos didn't understand her true nature as a green dragon. Raishan, somehow, helped release Thordak by ripping open a rift to the Elemental Plane of Fire in the side of the volcano.

It is unclear if Vox Machina saw Raishan in her humanoid form during Keyleth's Aramente in the episode.

On the Stream
Raishan was the third member of the Chroma Conclave encountered by Vox Machina (the first being Brimscythe, whom they slew before the Critical Role stream, and the second being Thordak, from whom they hid while in the Elemental Plane of Fire in ).

In, Raishan encountered Vox Machina when she and the rest of the Chroma Conclave interrupted Sovereign Uriel Tal'Dorei III's abdication speech and laid waste to a large group of Tal'Dorei Council members and other political and economic elites in Emon. Uriel died from this attack, Gilmore was wounded, and some members of Vox Machina nearly died, as well.

Upon conquering Emon, Thordak, leader of the Chroma Conclave, ordered Raishan and Umbrasyl to their next objective; they obeyed and flew east. The next day, after losing her connection to the teleportation sigils in Westruun, Lady Allura scryed across Tal'Dorei, revealing to Vox Machina that eastern towns, including Westruun, had, indeed, been conquered, presumably by Raishan and Umbrasyl.

For some time after the initial attack, Raishan seemed to disappear, with nobody seeing or hearing anything about her current activities. She finally reappeared in Whitestone, where she revealed to Vox Machina that she had taken the form of Asum Emring. Raishan proposed an alliance of sorts with Vox Machina, saying that she wanted to take down the Cinder King, Thordak.