Path Diverges:
At this point you have three choices, head to the mission 13 at Sable Lowlands, mission 14 at Audvera Heights, or mission 15 at Mount Ithaca. Reminder: Going to mission 15 before completing mission 13 or 14, will render those missions unplayable. 
According to the Chaos Frame Guide, choosing this path will raise your Chaos Frame by 15.
Liedel can be recruited. 
Aisha can be recruited.
Vad can be recruited. ​
Saradin can be recruited.
Choosing this path appears to have no effect on Chaos Frame.
​
​Saradin can be recruited.
There are no other characters that can be recruited if choosing to go straight to mission 15.
​According to the Chaos Frame Guide, choosing this path will drop your Chaos Frame by 15.
​Aisha can be recruited.
Liedel can be recruited. ​
Vad can be recruited. 
​Saradin can be recruited.

​Path Diverges:
At this point you have two choices, head to the mission 16 at Azure Plains, or mission 17 at Mount Keryoleth. Completing mission 17 will open mission 18 at Wentinus. If mission 18 is completed before mission 16, the mission will become unplayable.
Choosing either path appears to have no effect on Chaos Frame.

Sheen can be recruited.
​Sheen can be recruited.

​Important Choice:
At the start of the mission you will be presented with a choice. Make peace with the Western Division or decline the offer. Below are all confirmed effects of this choice.
Making Peace
According to the Chaos Frame Guide, your chaos frame will raise by 20.
Baldwin will become the missions' boss encounter.
Ankiseth can be recruited at the end of the mission as long as you said "I can't do it" at mission 6.
Note: If Ankiseth does not join your army, a future scene will be altered.
Declining Peace
Choosing this choice appears to have no effect on your Chaos Frame.
Ankiseth will become the missions' boss encounter. He is not able to be recruited.
Ogre Battle 64 and all related material is (c) Quest/Nintendo/Atlus/Square Enix
Last Update: 7/13/2020
Addition Information from: Chaos Frame Guide, Prima's Ogre Battle 64 Guide, The Official Japanese Ogre Battle 64 Guide