Chapter 18: The Dread Isle

Objective	Boss	Units allowed	Units gained
Defeat nomad trooper, Uhai	Uhai	12	Dart(automatic), Fiora(speak with Florina)
Items droped by emeny	Items that you can steal from enemy		Chest/Village
Torch(staff), Orion's Bolt, Longbow, Nosferatu, Torch	Torch, Light Rune		None
Initial Enemy		Reinforcements
8 Cavalier, 5 Nomad, 2 Pirate, 1 Thief, 1 Archer, 1 Monk, 1 Shaman, 1 Myrmidon		6 Pirate

Shops:

None

To unlock chapter 18x, you'll have to finish this chapter in 18 turns or less.
There are fogs in this chapter, so bring any torches you have.
Break your army into 3 groups, one going east then south, one going south then east, and one stay behind to pertect Merlinus and fight the pirates that will show up as reinforcements. Let Florina stay behind with the third group so she can talk to Fiora and recruit her when she shows up on turn 3.
The boss is in the lower right corner of the map, bring a torch to see where exactly he is.

Boss Strategy:
Since Uhai has steel sword equiped at first, surround him with your units and attack from a distance with magic users and 2-ranged weapons. I was able to finish him off with my Lucius as a level 2 Bishop.