USS Pybus (CVE-34) was initially a United States Navy Bogue-class escort carrier.

The ship was transferred to the United Kingdom for service in the Royal Navy as the Ruler-class escort carrier HMS Emperor (D98) as part of the Lend-Lease program of World War II.

Entering service in 1943, the ship took part in operations against the Tirpitz and the invasions of Normandy and southern France.

The Bogue class were all larger and had a greater aircraft capacity than all the preceding American built escort carriers.

Pybus reported for duty with the Pacific Fleet after shakedown, in a temporary status, before she decommissioned on 6 August 1943 at New York.