ok so you save a picture of the hero you want like that:
(actually not like that ,i left some of the hair of the guy under him)
then you go to resource manage, choose monster folder and import.
you then right click and left click on the bg cause you don't want it in
you go to the monster tab, make a larger array and wow a black screen
you double click on the black screen and choose your imported hero
go to monster group tab, make a group with it and the result: