Zieg
"Even if one of us dies, our bonds of affection are forever."Zieg and Rose first met some 11,000 years ago before the start of the Dragon Campaign. It is likely Zieg was already the Red-Eye Dragoon and it was his spirit that alerted him that Rose was also a Dragoon. Zieg accompanied Rose when she killed the Darkness Dragon to obtain the Darkness Dragoon spirit though he might have not fought with her. At this point, the two were already involved with the war efforts and knew that they would be the definitive advantage for the humans.
At some point, the relationship between these two had blossomed into love. They became engaged sometime before the final battle at Kadessa. Apparently this wasn't confidential news as even Emperor Diaz was aware of this. Knowing that their love could be ill fated, he reminded the two that it was quite possible one of them might die in the battle to come. Taking the time to make sure they were serious, Diaz must thought of his Dragoons as more than just elite soldiers. Zieg answers that their love is eternal. Zieg appears to have been the dominate partner in the relationship. Rose also seem a little startled at the comment, possibly hinting Zieg was not open with his feelings very often.
Kadessa
"Let... go! Save yourself!"
During the battle at Kadessa, Rose and Zieg stuck together until the end. He saved her life at least once, pulling her away from Kanzas' explosion. It was also those two alone that went after Melbu Frahma, Zieg charging him while Rose watched. She saw the death of Melbu Frahma on Zieg's sword and the petrification spell cast on Zieg. With great concern for her lover, Rose searched the collapsing ruins and found Zieg, the spell also complete. Rose would not leave him, even after the spell was complete and was ripped away from him in the destruction. It is likely Michael had to drag her away from the falling city. Rose was devistated. She had lost her lover, her friends and gained a duty to create a cycle of death that would last milenna.
The spell was not eternal however. Even Melbu Frahma's power had its limits. Eventually after those millennia, the spell wore off and Zieg was alive once more. Finding himself in the ruins of a city he destroyed, it is unknown how he managed to leave and find his way to civilization. But he did manage to find the new Mille Seseau, something that likely shocked him. Kadessa looked like it did 11,000 years ago but everything else was now in the present. Zieg had to accept that everything he knew and loved had been dead for hundreds of years, included the woman he loved. This was likely devastating on his psyche however Zieg was able to adapt to this change and live the rest of his years in this future he had built.
Never the Same
"Stay here. Take care of Dart."
It is likely Zieg was not able to get over the loss of Rose completely. It's possible he married Claire to get over Rose but at the same time, she resembled Rose in both personality and appearance. He probably wasn't trying to recreate Rose but at the same time, he couldn't truly replace her. Zieg did truly love her and their son and was determined to defeat this 'Black Monster' that had threatened their home. Unfortunately but trying to transform, Zieg awoke the Wingly Emperor that had been sleeping inside the Red-Eye Dragoon Spirit and became possessed. Without his own will, Zieg left the burning village without encountering the Black Monster. If he had, both Rose and Zieg would have learned of the other's existence. Claire also went back to Neet to fight and was killed by the Black Monster.
Return From the Dead
"You died!! With Melbu Frahma on each other's swords!! "
Zieg spends most of the game possessed by Melbu Frahma and it is his actions that brings about the destruction of the Signet Spheres and the birth of the God of Destruction. When he finally revealed himself, Rose was unable to accept her lover is standing in front of her. He was dead. He had died. He and Melbu Frahma had died on each other's swords. It was inconceivable to her that Zieg Feld could be alive and plotting the world's destruction.
It is likely that Melbu Frahma had every intention of hurting Rose the best way he could. There is no doubt of his anger at the destruction of his empire and being the last remaining Dragoon, Rose was a suitable target for his hate. Already overwhelmed with the knowledge her lover was alive, he proceeded to tell Dart that Rose was the Black Monster. While Rose was not ashamed of her actions, she had not yet figured out how to explain this to Dart and having it revealed by the man she loved was not something she had planed. Rose does not ask forgiveness, only justified her actions. But this was not the end of the revelations.
Zieg proceeded to tell Rose she had killed the wrong child and he was going to destroy the world. This knowledge is possibly the most devastating as it would imply Rose had destroyed an entire town for nothing. Not only a town but Dart's family. Rose savagely goes after Shana only to be blocked by a shield. With the departure of Zieg and Shana, Rose is left knowing her lover was alive, he had married another woman and their child was Dart, that everyone knew she was the Black Monster and she had failed in her most important task. As much at this hurt Rose, the real Zieg was likely just as hurt. He had to watch as Melbu Frahma, his most hated enemy, hurt the woman he loved. There was nothing he could do about it.
After this event. Rose seems determined to fix everything herself. Heading to Ulara to talk to the one person who could understand and help, Rose's new friends try to convince her that they can lighten her burden. Rose is troubled by the recent events, even if she is able to hide her emotions. However Dart is able to sense Rose's conflicted emotions, even to the point of being somewhat scared of what the future might bring. Dart's presence makes it easier for Rose to accept these events and focus on what matters.
After the encounters in Aglis and Zenebatos, Rose begins to believe less and less that the man before her is truly Zieg. He does not act like Zieg. A man who gave his life to take back the world from Wingly oppressors would not try to destroy it. He can perform magic, he can fly. These are all things that Zieg, a human, could not do. By the time Rose and Dart face Zieg at the Moon That Never Sets, she is determined to learn the truth about Zieg.
I'll Take That
"Everything was born to die!! It’s the same for spirits or the world!! Learn through your body!! "
To everyone's surprise, the Red-Eye Dragoon Spirit still recognized Zieg. Taking it, Zieg transformed into his former persona and challenged Dart. After defeating Zieg, Melbu Frahma leaves Zieg and merges with the Virage Embryo. He becomes the new God of Destruction and as a result spares Shana from this fate. Rose is reunited with the real Zieg at last. However they must defeat Melbu before the world is destroyed.
Even after defeating the God, he was determined to destroy everything. Rose and Zieg come to an understanding. Their time was over years ago. They decided to end it together. Killing Melbu Frahma and the God of Destruction, Zieg and Rose embrace for the last time. There are no words past between the two. Simply being together for one last time was enough. Even after everything they had been though, their love lasted eons and was rewarded with one last moment together before their deaths.