Fire Emblem: Path of Radiance/Chapter 6: A Brief Diversion

The Greil mercenaries left their fort after defeating a Daein regiment before the survivors brought reinforcements. They fled south and are being chased by General Petrine, who, with the help of Ena, predicted their every move. The Greil mercenaries are forced to split into two group, one to act as a diversionary team to lead the pursuers away and another to take the Princess further into Gallia where she can be safe. The diversionary team is Gatrie, Shinon and Greil while Ike and the others are given the duty of protecting Princess Elincia.

Walkthrough
Reposition Rhys and Soren so that they are on the front line of the group and trade any items you wish. Move the group to the south-west corner of the thickets and then you should start your attack.

Use Ike, Oscar and Gatrie to clear out the enemies on the bridge with the help of Soren's magic and make your way to the boss, making sure that Rhys and Soren are out of Danger's way. Eventually the boss will order his troops to charge. Use Titania to deal with any enemies that are coming from behind and Oscar and Boyd to deal with the threats in the East. Be careful, however, there is a knight with a poleaxe which will do additional damage to Oscar.

Once the enemies have been cleared out you should deal with the two soldiers on either side of the boss. If you used him enough, Soren should take care of these while using Rhys to heal him. Make sure he isn't attacked by the boss however as that would prove fatal. Once they have been defeated use Oscar, Boyd and Ike to kill the boss and make sure all of your characters escape, the last to escape should be Ike.