Isn't that a lot of polygons for Heroes 5?!
For Heroes 5, you'll need to retopologize it over the high-poly model, create a low-poly version, and then "bake" it. =)
Added 1 hour 36 minutes later
I modeled a box =)
In Heroes 3, there was the Pandora's Box.
You can rotate and zoom in here


Original (reference)