Instructions
Get to Chapter 11. This is the point in the game where you first encounter Jill.
Kill the vigilantes. There are four vigilantes on this level. Kill three of them but, if possible, leave the one named Zihark alive. He can be recruited if you let him talk to either Lethe or Mordecai.
Use Nephenee to engage the enemies in the bottom left corner of the map. This will allow you to move around more easily without being attacked.
Move from the bottom right corner on the map towards the boss, Mackoya, who is located in the top left corner. Jill will appear in the bottom right corner along with two wyvern riders at the end of turn four. Try and stay away from Jill for now because she is an enemy and attacks if you get too close.
Kill Mackoya. A good strategy is to try and lure him out into the open so that you can surround and attack him with your army.
Take out the guard that is standing on the blue square in the top left corner.
Place a member of your army on the blue square and select the action "Arrive" to complete the chapter.
Begin Chapter 12. At the end of the second turn, Jill flies onto the map and talks to Ike who recruits her into your army.