I used T1ckL35's file to add a jetpack. The jetpack I found was on cults3d. Here's the link: https://cults3d.com/en/3d-model/game/lego-jetpack-shreck. I added enough space to allow space in between the jetpack and the Minifig to have a cape.
mandoarmorjetpack.stl | 1.7MB |