The "Temptation" scenario.

There are upgraded units of all levels, and they join you. I also captured a mine guarded by horses, but I didn't bother with the elementals because they're fire-based. Then, I cleared the tower, killed the dryads, and upgraded all the old units. I also took some rakshasas from the garrisons and upgraded them. In the end, I had about 25 rakshasas and 60 mages, etc. Making phantom rakshasas is awesome. By the way, if you defeat a bunch of phoenixes, you'll see a little airplane in the mountains. It's not very effective against Markal, but it might satisfy your curiosity.