Their beginning was like a fairy tale; their beginning was something that seemed unreal now after everything they had been through.
Margaret was the daughter of the King Baltra; Gilthunder was the son of the Great Holy Knight Zaratras. Gilthunder swore to protect Margaret at a young age and Margaret swore to do the same for him.
At first their relationship was happy with very few worries, as most young loves were but that all changed far too soon. When Gilthunder's father died a mage named Vivian took advantage of the situation, she imprisoned the two and threatened to kill the other if one didn't do anything she ordered.
Their sweet beginning turned into a bitter middle. A middle filled with fear and regret. Eventually the Holy Knights took over the Kingdom, something both of them helped with. Margaret was locked up in the castle dungeon and Gilthunder continued to act the part of a cold, ruthless Holy Knight.
But they both had hope, hope that one day they would be free. Free to be together as they desired once more. Occasionally that hope wavered but it always steadied again.
One day their hopes came true and they were free. They could finally be together again but that didn't last long. Gilthunder had to atone for his sins and he couldn't do that staying with Margaret, as much as he wanted to stay with the woman he loved… he couldn't and so... Margaret let him go.
When they were reunited once more the Ten Commandments were free, Meliodas was dead and Britannia was in so much danger. The second Holy War had begun. They were reunited under terrible circumstances but still the two had hope that everything would turn out alright.
That was when Gilfrost, who had been Vivian in disguise, took Gilthunder away. To where? Margaret wasn't sure, but Margaret was sick of waiting for everything to turn out alright. She was going to make sure she and Gilthunder got their happy ending.
Margaret was going to find Gilthunder and Vivian, rescue her love from Vivian's clutches and the two would finally have their happy ending. She would make sure of that… even if she had to do it all by herself.
They would have an ending as happy as their beginning, no their ending would be even happier than their beginning had been.