Got it! If so, you cannot really animate a cape as part of the character. You’ll have to find another workaround.
The first workaround would be to use APEX cloth for the cape.
The second workaround would be to build the cape as a separate mesh, with a separate skeleton, and separate animations, and attach it to a socket on the base character.
There is some tutorial content from Epic that uses a guy with a cape; you might be able to pick that apart and see how it’s done.
(IIRC, some of the networked gameplay tutorials have that character?)