Fire Emblem: Shadow Dragon/Chapter 24

The Dragonkin Realm

"Doluna...Land of the Manaketes. Before Medeus, the dragonkin had few dealings with the human realm, but when the Shadow Dragon came, everything changed. He sunk all Akaneia into a cycle of war, in which heroes rose and heroes fell- always claiming his cause was just and the human deaths deserved. But now Medeus's empire was crumbling...He was nearing the end of his reign...even as Marth was nearing then end of his long quest."

Begin
First turn, kill the thief with Beck. Then, move the rest of your units forward

There are two types of Manaketes here, the ones with Firestones and the ones with Magestones. The latter is by far more powerful and it is best to use the strongest of your units to kill them.

Your units should be able to conquer the east side with ease, but the hard part is holding it. Send a unit like Wolf through the gap in the mountains to the left.

Send a flying unit armed with a dragonpike to fight the boss. If you defeat him the reinforcements won't come. This map is hard because there seems to be an endless amount of reinforcements if you let it happen.

As soon as it is possible, put a unit on the forts to the south and east. These are really annoying and unless you need experience, stay away.

These units are enough to cause trouble, make sure to keep good units to beat them. The goal to stop these reinforcements is to simply not let them spawn in, put a unit on the fort to quell resistance. Thankfully, the boss cannot attack further than 1 range, so you are free to place two units on the forts there. A flier is recommended to capture the base that the Manakete spawns in.

After all this fighting (you have to kill the rest of the stationary units before the above is even considered), you should only have the fortress and the boss left.

For the fortress, just overpower it with strong units. The chest in there contains the Aum staff, which allows you to resurrect a lost unit.

Seize the gate after defeating the boss.