Sword and Shield of Seiros

The town has two gates that you must defend; the main gate to the east and the other gate to the south. If any of the pirates get into town and remained there for at least 5 turns, you’ll fail the mission. You don’t have to block the gates with your units.

You can proactively go out and engage the enemies, as long as you’re able to take them out quickly. The battle ends if you finish off the pirate captain. To maximize the rewards, save the captain for last and bring at least one Flier.

Enemy wyvern riders are dangerous especially if they attack your softer units. Have archers or mages ready to deal with them.

One of the boats in the northeast will always release two enemy units. It’s possible to farm this spot if you feel like it.

Move your units and fight your way through enemy positions, as you surround the pirate captain. He won’t move from his position unless you enter his Attack Range so you can take your time moving your units close together to prevent them from getting isolated and picked off one by one. Once in Range, gang up and finish off the pirate captain to complete the mission.