Your initial location:
Place Feena and a combat unit in spots 4 and 5 so you can kill the thief in the first turn. Other than that it doesn’t matter where you place your characters. Also make sure to bring the Light orb, the Miracle Sword and the Parthia. If you want to recruit Midia, don’t forget to bring Yumina and her rescue staff. A thief is convenient too.
Your first opponent is a Hero with a Silver Sword. Lure him with someone who doesn’t get double attacked (and equipped with the Life Orb) and kill him in your turn. It’s also suggested to rescue Midia and equip her right away; she may not be close to being the best unit in the game but you can at least give her some use in this chapter.
Now, the chest located in the room north of the map contains a Lady Sword. If you want to get it, a good start is to snipe the mages and the sniper. The tile where I placed Linda is the most convenient location for this. You can send any strong ranged unit, though my favorite option is Linda with the Resire tome. As shown in the following image use another set of units to lure and kill the other hero, just don’t lure him with a hero of your own as he has a Sword Killer.
The room with the treasure chests is the safest route to reaching Hardin (there’s an Earth Dragon in the other road, identical to the final boss of Book 1) but before entering, snipe the enemies in range.
From here it’s pretty straightforward. Your priority is to kill the bishops with long range spells, then collect the treasure and before opening the door that leads to Hardin, kill the dark mage and sniper. The dark mage has a Dulam spell, which brings your character’s HP down to 1, if it hits, so be careful there and don’t forget to heal if it hits.
Once you open the door, a room with a treasure chest will open and reinforcements will come. The treasure chest contains a devil sword; I highly suggest to ignore it and just clear the chapter as fast as possible. In an ideal world, your Miracle Sword user lands 20 damage per hit to Hardin, and due to the Gradius, his attack speed is low (12) so you should deal around 40 damage, maybe a bit less, or instantly kill him in one round with a critical hit. However, if he survives this round of combat, you should either use Feena on your Miracle Sword user or your Parthia user, or Linda/Marich (Aura/Excalibur) to finish him off. It’s very important that the unit that attacks Hardin has the Light orb, and preferably the Star Orb so your weapons remain intact.
As you can see, this chapter can be a bit tricky. The key factors here are to place your units with caution so the long range magic units don’t kill them, attack before opening the doors and defeat Hardin in one turn if possible.
OK, now that you finished this chapter and the Fire Emblem is complete it’s time to move on to the last portion of the game.