Fire Emblem: The Sacred Stones/Chapter 3: The Bandits of Borgo

Seize the throne
Send Neimi up to speak with Colm when he appears at the end of turn 1. Have everyone else break through the cracked walls of the two rooms east of the starting point. Defeat the bandit in the southern room, get the javelin from the chest, and use combined direct and ranged attacks to take out the bandit in the north room. After, use the door key to open the door between the two rooms and send everyone up without straying into the bandit in the northernmost room's range. Have Colm, Neimi, and another weaker character take out that bandit, then send everyone but Ross and Franz (who should have been given the javelin) into the room. Get Colm to steal the contents of the room's three chests, then distribute them to your units. Meanwhile, get Ross to take out the Brigand on the other side of the cracked wall while Franz attacks the Thief below him. If the Thief survives until your units enter that main room, he'll steal all their loot, and you'll have to get Colm to steal it back if you want it. Once the western side of the main room is cleared, break the cracked wall on its west wall and have Colm open the door in its north wall. Storm in and defeat all but Bazba and his bodyguard. Then have your weaker units and one strong unit position themselves around Bazba.

Boss: Bazba
Bazba is tough. The good news is that you can attack him from six spaces. You'll probably want to use Neimi, Ross, and Garcia to attack with the iron bow, hatchet, and hand axe respectively, all from two spaces away. Equip a sword to Franz and have him attack from one space away. Do the same with Eirika, using the rapier if necessary. Keep Seth in the background in case they can't all topple him in one turn, because he'll probably counter-attack against Neimi with his hand axe and kill her. Keep Gilliam and Vanessa away; they have a very low chance of hitting Bazba. Alternatively you can level up Ross very easily with this boss. Attack with Ross from a distance, then use Vanessa to rescue and Moulder to drop Ross back onto the field. This way, Bazba will never switch to his projectile weapon which means that you will always be able to hit him from a distance. This strategy works wonders against almost every boss in the game.