One is not enough
Disclaimer: Of course I own nothing. Just the plot.
Wanting to forget everything, wanting to wash the unshed tears, she fights herself. She practices, she throws, letting her weapons soar freely in a way she can't until they hit bull's-eye.
That dark-self hid for a while inside her, now wanting to come out. She refuses to, but her body says otherwise. While soaring with her blades she can be herself for a while, calming that demon, but when she reaches the ground, it becomes even more unbearable. It only desires to kill and torture, all that great dark power still to be tested.
Miss Darkness, as she calls it, is now a step from being free…
He notices it, as he always did for so long. Now he watches her struggle, never brave enough to help her. Fear of rejection and humiliation but also the thought of she never being herself again haunts him knowing he too feels sick inside, not as much as her though.
Finally one day, while watching her panicking to the point she tried stopping herself, he takes action. Blade in one hand, the other wiping long needed crystalline tears. She tries death this time, not considering a different escape. He jumps in, right before the blade slashes her throat. She looks at him questionably and breaks down crying. He holds her tightly, she sobbing on his chest.
He knows the nightmare is not over; he still needs to find a way to free her. Then he remembers the days he watched her and the times when she smiled.
He helps her get up, holding her hand, telling her he won't let go. She only smiles faintly at him and nods. He then tells her to fly with him. She stares at him but does what he says. Slowly both jump high in the air feeling the cool breeze. Up there, in the clouds she understands and smiles truly at him. She releases her weapons and lets them dance, the shining metal surrounding them. Inside him his heart calms down and he returns the smile. Dancing with her weapons and him healed her. He too feels relieved.
When back on the ground she feels light-headed and alive. He is too feeling better, as he looks into her eyes, all those feelings getting to her with just one look.
Both know what the other wants to say confirming things by locking their lips together.
Soaring, with him made Miss Darkness retrieve forever. Her lips made him realize he wasn't alone and needed only her to survive.
Now he is sure and she is sure. They are safe with each other. Soaring that his how.