Fire Emblem: Shadow Dragon/Chapter 3

A Brush in the Teeth "When journeying in from the borderlands, one particular peril would spring to mind: the Samsooth Mountains, whose gashing peaks rose up and divided the peni- nsula. Since before anyone could remember, the mountains had belonged to band- its, blights on the land whose acts of plunder, kidnapping, and arson knew no bounds. Out of fear, their victims gave these peaks another name: the Ghoul's Teeth; while the bandits who ruled atop the Teeth's craggy crowns took a name as well: the Samsooth Sires, or Soothsires..."

Begin
You finally resume control of your characters. First thing you want to do is move Julian and Lena south. Have a few ready units to defend the area at the bottom.

Marth needs to head to the village. You will get a Devil Axe there. Rest of the units left should head left and confront the enemy there. Shiida is needed to recruit Nabarl, so she must be part of the group defending the area at the bottom.

After a few turns worth, you should have cleared both areas of danger with your respective units. The myridon, Nabarl, is reliable and you should keep him unless you plan on going to the gaiden chapters.

Don't worry about his Killing Edge breaking, he will get another one shortly.

The boss is just another generic boss, nothing special or dangerous...

Seize the gate.