It's a homebrew menu with a integrated .nds loader. The menu is M3 simply/R4DS basedand has to be patched with a dldi file of your card.You can skin this file with a M3 ds simply/R4DS skin, that you have renamed and converted to the .gif format
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)