Seir

Seir is a scout, a spy, a provocateur, and at times a double, triple, or quadruple agent. The White Cavalry of the Armageddon is responsible for recognizing and fomenting conquests of all sorts (even those that Hell might not be happy with). While their particular focus is the breaking of the First Seal, these scouts will also keep an eye out for the warning signs of any other apocalyptic scenarios.
Officially, Seir is on loan to Nybbas. However, they are known to have worked for Genubath, Legion, Laurence, Khalid, Makatiel, and Valefor each in turn. Their command is lousy with agents from Heaven and Hell (both those with assignments to report signs of the Apocalypse back to their respective Superiors, and those on the hunt for traitors and apostates).
Because the White Cavalry of the Armageddon has been known to include both angels and demons, it is an ideal setting for a mixed party.