The spell is made through JASS and probably has many triggers. You can do the following thing as long as you want like Darky's (hope you can use main triggers though). When the caster activates the spell you add it to a game cache and replace it with your new hero. Once the new hero changes again you add it to the game cache and load the other hero from the game cache by removing IT. This will keep all the items and stuff. To transfer items from one hero to another... I think this already requires JASS so it's beyound my comprehension.
