Lightning
Valhalla
Caius was unrelenting. When he came to Valhalla to challenge Etro's guardian, he showed neither mercy nor quarter. Lightning enjoyed a good fight every now and again, but Caius was a true warrior. Killing was in his blood. He thrived in battle; drank in every clash of swords like an elixir. He never showed weakness and never tired.
He flattered her. He called Lightning "Warrior Goddess." He said they were equals in battle.
Lightning knew he was lying. Caius was centuries—perhaps millennia—old. He knew things she could not even hope to learn. This battle was just a ruse. He had been putting on this performance since their first round. Caius was testing her, pushing her a little further every time they met in battle. But Lightning knew the truth: he was going easy on her. He was letting her win.
Lightning surmised that her opponent wanted her to kill him, but he put up one hell of a fight.
She didn't know why he wanted to die, but nothing good could come of it. This proud warrior didn't seem like a man lost in despair looking for an honorable way out. He had already taught her countless things about the art of war. He was a fighter to be respected. When Caius retreated from Valhalla and Lightning was given a time of reprieve, Etro showed her visions of Caius in other battles. In every vision, a young girl watched from afar. Lightning realized Caius was some kind of bodyguard, protecting that little girl. She had immense respect for this man—this protector—who had seen so many eras pass.
She couldn't kill him. He had a duty to that girl.
So Lightning fought Caius of the Ballads. Every time an opportunity to end the battle presented itself, she held back. Usually after that critical moment, he would take his leave and allow Lightning to rest.
Caius seemed to grow angry with her because the time between battles shortened. It became less of a game of skill and more about survival. Caius wasn't holding back anymore. He must have realized Lightning had no intention of following along with his plan.
Lightning was tired. Exhausted. Her blade grew so heavy, her shield nearly impossible to lift. She had scratches on her face and neck from flying rubble disturbed by their offensive magic. She only wanted to sleep. She wanted the battle to end.
When Lightning's fatigue began to overcome her, Caius revealed that he was no longer looking for her assistance. Caius deemed Lightning unworthy of taking his life and had resolved to take hers instead.
After a particularly rigorous battle, as Lightning slumped against a broken pillar, she watched Caius step back and raise his arms into the air. A circle of purple magic appeared in the sky. The hairs on her arms raised, the air smelled like metal and steam. She remembered this sensation from her time fighting with her l'Cie companions. She could smell machination and energy whenever an Eidolon was summoned. Her stomach dropped.
A thick, purple fog surrounded Caius until Lightning could only see two glowing violet eyes. The eyes shifted and grew, moving upward in the haze. A roar cut through the silent city, leaving her ears ringing.
When the smoke cleared, Lightning saw only a bahamut; many times larger than Fang's Eidolon. Another roar escaped his gaping jaws and he fixed those same glowing eyes in Lightning's direction.
She took up her sword and cast her eyes around frantically, searching for Caius. He was gone. He might have fled Valhalla, leaving this beast to take care of Lightning. But she knew the more likely answer.
Caius had become his Eidolon. He had transformed into the bahamut.
Lightning had never heard of this. She imagined the risk was incredible. Who would purposefully allow a monster to take over their body? Was this why Caius was so powerful? Did he exchange his humanity for this? Was this possession why he wanted Lightning to kill him?
She had enough time to stand up, her shield and sword at the ready, when Caius exhaled a blast of purple fire in her direction. Lightning jumped away, barely escaping the column of flame. She pulled the eidolith from her chest and threw it into the air. There was only one way she had any hope of surviving this onslaught. She shot the crystal with her gunblade and Odin appeared in a flurry of rose petals.
Lightning leapt into the saddle, suddenly more aware and energized than she had been before. This battle was far from over. She gave up the hope of ever going home. She would never see Serah's face again. However, she wouldn't let hopelessness overtake her. She could not allow Caius to succeed. Death would have to wait.