Hastur

Cassilda, meekly: "So you've conquered all of Hastur, then?"

The King: "WE ARE HASTUR. WE HAVE MERELY RECLAIMED YHTILL FROM THE INFESTATION WHICH HAS PLAGUED IT."

The King in Yellow

Hastur is one of the five Lloigor--though It might be more accurately described as a Zharnos--which are present on Earth.