In 1944, "
House of Frankenstein" was released, which was followed by "House of Dracula" in 1945. Apparently, "House of the Wolf Man" was supposed to happen soon after, but never did. So director Eben Mcgarr took it upon himself to make that third film, which stars Ron Chaney, the grandson of Lon Chaney Jr (the original Wolf Man).
How very cool!
-c