Inferno has the ability to open gates, and when combined with Urgash's Call + wide gates + fast gate opening, it becomes a unique advantage. Also, they have Chaos and Darkness spells in their guild of mages, as well as a lot of knowledge. For example, at level 23, the hero had 190 mana.
Urgash's Call still needs to be researched; it's enough to destroy the initial units, and the summoned creatures will disappear on their own. :) 190 mana is, of course, good, but magic power is better! :) 100 is enough for one battle, and then the Warlocks use Dark Ritual. And the high spell power of the Warlocks, enhanced spells, wizard's luck, and meteor shower will wipe everyone out! :) Even mages won't be able to deflect Meteor Shower! :) High attack, powerful creatures of levels 1-4. :) The only drawback is low defense. :( But there is plenty of knowledge!