In my opinion, the most effective early game strategy for the Inferno faction involves using Deleb. And if Grog appears in the tavern right away, these two together can catch the opponent off guard, which is essentially their goal. Inferno units often overwhelm the opponent with their high initiative, so the primary task is to exert maximum pressure and deprive the opponent of space on the battlefield. The Inferno faction also has heroes like Jezebeth, Grol, and Alastor, who can become decent Dark or Chaos heroes, but this requires effort to acquire spells and knowledge, as well as collect the appropriate artifacts. Creating a phantom works very well. In the late game, I think Nimue is a good choice, as she can overwhelm the enemy with sheer numbers, regardless of the opponent. If your opponent is a mage, Marbas can be effective in the late game due to his ability. Overall, the faction is not bad, but in my opinion, the chances of winning in the late game are not that great, especially against defensive builds of Dwarves or Elves, which rely on a solid defense or preparedness. Therefore, it is necessary to put pressure on the opponent early on.
*Of course, I'm talking about the "Hero" difficulty level and when you are given archers or someone else for the mines. What will you do in the first few turns? And what will a Necromancer or even a Dark Knight do, who at least has a Guild on Tier 1 and can quickly build up a ranged unit stack? Even the Order or Horde can find a strong early game stack in the form of archers or Nomadic Centaurs, of course, with the support of a Ballista :D