Rogu the Sigillite, also known as Rogu, is the close advisor to Roger the Alien, the close advisor to the Emperor of Stan.
The episode depicting Rogu’s origins has been retrieved by the Chapter. It is one of the most valuable episodes that the Imperium of Stan has recovered. It is known that Rogu the Sigillite was created from Roger the Alien. Therefore, the Chapter worships both as the Emperor’s closest confidants.
Similar to Roger, Rogu is also a Xenos Psyker with a strong connection to the Warp. However, he is generally considered to be less powerful than Roger.