Shot from a personal mod for Heroes VII, made by evilp.
According to the maker, "In H7 map editor h7 mode you can easily add simple new artifacts and heroes for single map. But in ue3 mode, you can do more, create new artifacts, artifacts sets, new heros with new specializations for all maps."
If you want to try it, the mod is here: http://heroworld.gamerhome.net/private/evilp/h7hero/H7Config.7z
Replace the file GAMEDIR\MMH7Game\CookedPC\Data\H7Config.upk. A backup file is in bak folder if you forget to backup the original H7Config.upk