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Fiona Jarnefeldt
General information
Classification Human
Gender Female
Affiliation and military information
Affiliation Anatolia,
Line Ark
Occupation Operator,
NEXT engineer[1]
Eras present National Dismantlement War,
Pax Economica,
Lynx War,
Economic War
Known battles Battle at the Abandoned City
Real world information
Appearances Armored Core 4,
Armored Core: For Answer,
Armored Core: A New Order of "NEXT",
Armored Core Designs 4 & for Answer
Voice actor English: Kari Wahlgren
Japanese: Maaya Sakamoto

Fiona Jarnefeldt is the Operator for the Lynx known as "Anatolia's Mercenary." She works together with the mercenary and Emill Gustav to support the colony Anatolia following the death of her father, Professor Jarnefeldt, a renowned scientist who had single-handedly sustained the colony.

By the Economic War, she remains with her Lynx ⁠— now referred to as "White Glint" ⁠from his eponymous NEXT — while working together for Line Ark, a maritime city-state that opposes the League of Ruling Companies.


Sometime after the National Dismantlement War, Fiona saved a legendary Raven and took him to Anatolia. Four years after the war, Professor Jarnefeldt died and many of Anatolia's key researchers left for the Aspina colony, sending Anatolia into an economic crisis. In response, the new leader of the colony and a former aide to Fiona's father, Emill Gustav suggested that they have the Raven, who possessed the minimum AMS compatibility needed to be a Lynx, pilot the NEXT Emill owned for research purposes to act as a mercenary for the colony. Fiona, a talented NEXT engineer herself, opposed the idea due to the dangers of Kojima pollution as well as AMS' high mental load on pilots with low AMS aptitude like the Raven. Eventually, the Raven does become a Lynx, so Fiona volunteers to be his Operator to help him even just a little.[2][1]

Fiona shows considerable guilt in using the mercenary to sustain Anatolia and sometimes even breaks protocols to ensure her partner's safety. Unlike Emill, Fiona is naive and optimistic — although she does assist in destroying targets, Fiona often questions the need to do so and demonstrates sorrow and regret during debriefings.

Later on, the fall of the Rayleonard corporation's headquarters Exavil at the hands of Anatolia's Mercenary in conjunction with Akvavit's defeat signals the end of the Lynx War. The mercenary's numerous victories secures Anatolia's financial stability, so Fiona and her partner leave for a vacation.[3] In their absence, however, the colony is attacked by the 00-ARETHA, a powerful prototype NEXT designed by Fiona's father and piloted by Joshua O'Brien, a friend of Fiona and the mercenary, as well as an Aspina Lynx; O'Brien is blackmailed by Omer Science Technology into destroying Anatolia under the threat of his colony's destruction. Fiona recognizes the ARETHA and races back to Anatolia together with her partner but it is already in flames when they return. O'Brien is killed in the ensuing battle. Afterwards, Fiona takes the mercenary and leaves Anatolia for good.[4][5]

More than a decade later, Fiona and the mercenary work for Line Ark where her partner, "White Glint," serves as its guardian and ace-in-the-hole. Fiona has matured considerably, lacking the innocent and naive personality displayed before.[6]

Following White Glint's defeat, Fiona is tasked with finding Line Ark a new NEXT. In an interview with a journalist, she expresses her suspicions regarding the ORCA Brigade's intentions and reveals that Line Ark has a Lynx ready, though she refuses to answer when asked if the Lynx in question is the White Glint.[7]


Armored Core 4[]

"First Strike"[]

  • "Now commencing mission. Normals are the enemy's primary force--eliminate them."
  • If an enemy Normal is sighted for the first time:
"Enemy normal confirmed. There's your target—take it out."
  • If all enemy Normals are Destroyed:
"All enemy Normals destroyed. Mission accomplished. Come on home."
  • Debriefing:
"You did brilliantly - Emil is ecstatic. I'm sure he'll do his part. Then, you'll be sent back into the fray."

"Swarms of Red Eyes"[]

  • Briefing:
"Let's confirm the mission. A fleet of unidentified submarines is closing on the Eocene launch site. The ships' wake characteristics indicate they're Omer's Safi-class special subs, likely loaded with Omer's explosive self-destruct weapons. You'll stand by on the peninsula and intercept the incoming self-destruct weapons with a volley of fire as they approach the launch site from the shore. Those are your orders."
  • "We've confirmed the self-destruct devices' approach. They're right on schedule with our projections. Prepare to intercept. The enemy fleet has hit shore. Take a deep breath and move out."
  • "Enemy submarine fleet is withdrawing!"
  • "The enemy self destruct units are withdrawing. There's barely a scratch on the launch site. Please head back."
  • "You got the whole pack. Zero damage reported from the launch site. Mission accomplished --a perfect result. Good work. Please head back."

Armored Core: For Answer[]

"Defeat White Glint"[]

  • First cutscene:
"This is the Operator of White Glint. You are trespassing in Line Ark territory. Pull back immediately... or we will respond with lethal force."
  • "It looks like you came to fight."
  • "You are the same as we once were. Think. What are you fighting for?"
  • If the player's AP drops to 50%:
"Please leave. I know how this will end."

"Defend Line Ark"[]

  • "White Glint operator, Fiona Jarnefeldt here. I appreciate the assistance. Good luck to both of us."
  • If White Glint is defeated:
"White Glint is disabled. He cannot come to your help any longer. I'm sorry."
"Fellow Lynx, allow me to express our gratitude. Thank you. However, this might mean the end of Line Ark."


Fiona is a friendly NPC in Armored Core 4 where she serves as the player's Operator throughout the entire game, providing the pre-mission briefings and debriefings as well as instructions and status updates during a mission proper. Like prior Operators in the series, she is largely an off-screen character presented in-game through voice lines. The only exception to this is the opening cutscene of Chapter 1 where Fiona can be seen, albeit with her face covered by shadow.

She returns in Armored Core: For Answer as the Operator for the White Glint. Fiona is a hostile NPC in "Defeat White Glint" where she warns Strayed (the player) and League Lynx Otsdarva that the White Glint will respond with lethal force should they refuse to leave Line Ark. She will proceed to resign to the fight once Otsdarva makes it clear that the League intends to defeat White Glint. Later on in the mission, Strayed will be noted by Fiona to be the same as her and White Glint during the Lynx War and will then be implored by Fiona to contemplate their reason for fighting. Should the player's AP falls to fifty-percent at any point, then she will determine that White Glint has already won so she politely asks Strayed to leave.

In "Defend Line Ark", on the other hand, she communicates to Strayed on White Glint's behalf, thanking them for their cooperation and apologizing once White Glint is defeated.



  1. 1.0 1.1 Armored Core: A New Order of "NEXT", page 57
  2. Armored Core 4, Chapter 1 opening cutscene
  3. Armored Core 4, "Bitter Obligation"
  4. Armored Core 4, "Seed a Barren Earth"
  5. Armored Core 4, Post-ending credits cutscene
  6. Armored Core: For Answer
  7. Armored Core: A New Order of "NEXT", page 48