Using Infinity Blade / Paragon Assets as showcase for blueprint systems to sell on the marketplace?

Does somebody know if it is allowed to add infinity blade or paragon assets to my project which i want to sell on the marketplace to demonstrate the blueprints i created. The main part is defintely the blueprints and the ib/paragon assets would only be used to demonstrate the working of those blueprints.

Or do i specifically need the permission of epic games for that?

There is also a marketplace assets (Dynamic Combat/Magic System) which uses the Dino (Buff_Yellow) of the Paragon Minions as an ai test dummy, but i am unsure if they author got the specific permission or if it is generally accepted.

Mfg/ Kind regards.