This project aims to port DeSmuME to Wii homebrew so that we can have a fully fledged, working, Nintendo DS emulator on Wii. It is being built with DeSmuME 0.95 and the latest available devkitPPC and libogc releases
I don't have a wii u anymore to test it myself, but if homebrews are not visible on the wii u menu I think you can press L + R + minus to open the plugin menu, there should be an option called "homebrews on wii u menu" or something similar
Or when your player dies, you can say in code, if enemy exists, do nothing, but if enemy does not exist, then create enemy at certain spot. (This would be a pain tho for lots of emeies)