Who plays with which heroes in the Inferno faction?

For the Call of Urgash, it's better to use Nimues. In addition to this, level up his Luck, "Wide Gates of Hell," and "Master of Gates." He will be a strong hero, unlike your Grok... who has very few reinforcements.

Grok can also level up the same abilities. To get them, Nimues will need another 32 levels, and it's not a given that they will even appear. And to gain that much experience... how much do you have to play and how much of the map do you have to explore? No, Grok is better because he will gain experience much faster thanks to his speed. He will be stronger and in the early game, he can easily defeat neutral archers with his teleport.