Reign of chaos ability

Hey guys i have a question for you. How can i make Reign of chaos non targetable. So basically i want the infernals to fall around my charactar right after the ability is chosen. I dont want my charactar to able to target the area for summon.

If you guys know anything plz help me out thx

you will have to create an ability based on thunderclap or some other untargetable ability then have a trigger create a dummy unit and cast the spell for the hero.