This character would still count as a fandom OC. In order to app him to Duplicity, you would need to change details about his background enough to make him a full OC with no fandom ties. CRAU from other games is allowed, however we would need to see how it is in presented in an app to know for sure if it would be fully accepted. Depending on the way things worked in the other game, we may require certain changes or retcons.