You prepare to assist with the operation against the Imperial forces and their Magitek prototypes.
This quest is available if you have completed the quest Signed, Sealed, to Be Delivered.
Starting the Quest
Talk to Raubahn in Castrum Oriens in the Fringes to begin the quest.
Lie in Wait
Go southeast through the wall of the Castrum, then go east to where the orange arrow is pointing in the minimap. Check on the Destination, then kill the Imperial Signifer, followed by the Imperial Laquearius.
Rendezvous with Raubahn
Go northwest to the dirt path, then go west up the slope, continue west and cross the bridge, then go south to where the orange arrow is pointing in the map. There will be a glow around Raubahn, indicating an instanced battle. Check on Raubahn and there will be a cutscene, and then the battle will ensue.
Solo Duty: Best Served with Cold Steel
Whenever 12th Legion Slashers appear, defeat them first. If there aren't any, attack the Magitek Vanguard I Prototype.
Dodge attack markers and stay near Alisaie so she can heal you.
When two 12th Legion Signifers and two 12th Legion Hoplomachi appear, defeat the Signifers first, then the Hoplomachi.
You will sometimes be tethered by one more more untargeteable Magitek Bits. Run away from the bit or bits that are tethering you, because they will soon use Self-Detonate, which will damage you if you are near them.
When a large number of 12th Legion Slashers appears, make them go near Raubahn so that they will be in the range of the blue attack circle and be damaged by Raubahn's attack.
After a while, there will be a cutscene.
After the cutscene, focus all attacks on the Magitek Vanguard I Prototype and defeat it as quickly as possible so it is destroyed before it can finish casting Self-Detonate.
Afterward, there will be a cutscene.
Speak with M'naago
Talk to M'naago to complete the quest.
Next Main Scenario Quest
After you complete the quest, talk to M'naago to accept the next quest: Let Fill Your Hearts with Pride.