Inferno tactics.

Back in the day, I spent a lot of time playing as the Dungeon. In my opinion, Inferno stands out positively among the factions. Imps are great against hero-mages. Magogs are good. They are excellent in the early stages. And those who say that magogs hit their own units when firing are simply not skilled at using them. Cerberuses – beware! Good growth, decent stats, and retaliation. Cerberuses rule at level 3 (except against elves). Demons and fiends. In principle, they provide an impressive but not very effective combination. Efreeti. No need for comments. Devils look "not bad" thanks to retaliation and teleportation. In theory, they should be effective against angels, but in practice, it doesn't always work out that way.
The Magic Guild is good – 5 levels. The heroes are unremarkable, except perhaps for Zydar. So, use him. Inferno has the Gates of Hell. If the secondary faction is Inferno, it turns out to be quite interesting, although expensive.
Overall, Inferno is doing a good job. They just need a good commander and a bit of luck...