Taking the maximum Griffin Conservatory for Inferno on lava with a 2nd-week bonus:

Setup: 1-6 with a castle, no dogs.
Army: 80 Imps, 36 Magogs, 9 Pitfiends, 12 Demons, 6 Efreet, 30 Trogols, or another army from the left hero that won't die after the first Griffin attack.

Hero - Marius with Expert Armor. Attack/Defense 5-8.

General Considerations: Out of 10 attempts, it was possible to win in seven cases. Critical moments: it's very bad if morale triggers for the distant Griffins in the first two rounds; then the battle can be lost if morale triggers 1-2 more times. In a real game, Demon units usually also level up Knowledge and Strength, and the Grand Mage is already built by the 1st week. Therefore, with a spellbook, the probability of winning increases significantly (if there's Bless, it's >90%). It's also good to have Shield or Stone Skin; then, one morale trigger for the distant Griffins won't affect the entire battle.
If attacking without a spellbook, it's desirable to have at least Advanced Ranged Attack (Expert is better), or the Spirit of Discord artifact, or morale boosters. 1-2 morale triggers on the Magogs throughout the battle noticeably eases the battle.
If there's a reserve of Demons or Magogs, the probability of success is also very high.

Also, if there's Offense, losses will be less.

Deployment (80 Imps, 12 Demons, 30 Trogols, 9 Pitfiends, 1 Imp, 36 Magogs, 6 Efreet)

Round 1:
Attack the bottom-left stack with Efreet, then attack with Imps. Move to the 2nd cell from the bottom left. Place 1 Imp on the 4th cell from the top right. Place the Demons directly above them on the right edge.
Attack the bottom-left stack again with Pitfiends; about 19 Griffins remain.
Shoot at the top-right with Magogs, killing ~5 Griffins.

The bottom-left Griffins attack the Trogols (morale is not critical). The top-left Griffins finish off the Trogols (morale is also not critical here). But there's a small chance that the first Griffins will attack the Magogs. Then GG. Therefore, if there's magic and Slow, slow down the top-left stack.
The distant Griffins kill the single Imp and surround the Demons.

Round 2: Attack the smaller stack of Griffins with Efreet. Wait with Imps.
Defend with Demons. If there's magic, cast Shield/Stone Skin on them; this will be insurance against morale.
Move the Pitfiends to the 2nd cell from the bottom left, creating a "pocket" and move the Magogs into it.

Now, if morale didn't trigger for the distant Griffins, they will stand in a stack on the right side of the screen.

The close Griffins attack the Imps (there's a small chance they'll attack the Efreet). Attack the large stack of Griffins with Imps, and they die in retaliation.

Round 3:

Move the Efreet to the place of the Imps and attack the large stack of Griffins. Attack the same stack with Pitfiends. Shoot at the distant stacks with Magogs. The close Griffins attack (most likely the Efreet); the distant ones fly in. With a spellbook, cast Bless/Accuracy on the Magogs or defensive spells here and further, or weaken the Griffins.

Round 4:

The Efreet and Pitfiends attack the large stack of Griffins. The Magogs wait; the distant Griffins fly in. If morale didn't trigger here and the Griffins became a pair, then you can consider that the battle is 95% won (now the only trouble can come from the large stack of Griffins in the next round), and it's just a matter of losses. Shoot at the pair with Magogs.

Round 5 and subsequent rounds:
Then, look at the situation; if any of our stacks are weak, defend with them; otherwise, we can attack or defend; shoot at the stacks with Magogs; if the cover is destroyed, finish them off in melee.

The best result without magic was: 3 surviving Pitfiends and two Efreet, all Magogs.