It was never supposed to end like this. She was supposed to save him, to take him back home and make him better. She didn't regret any step she made in the process - from loving him like the brother he was to leading him outside for a small taste of freedom - but she did regret the outcome. The darkness that had been inside him had only grown, making a monster out of the man that was once Marik Ishtar. Night fell and Ishizu knew for sure that she had been left for dead, lying right outside the hidden entrance to the Pharaoh's tombs. How bitterly ironic a place for Marik to leave her. How suitable a fate, after all that had happened.
A Tomb Keeper's life was destined to always be a solitary and long one. Their duties were to the dead, not to the living. And yet, she had sacrificed so much for that one person to whom in the end blood bonds meant nothing. She wasn't even sure he knew who she was anymore, so blinded by rage and revenge was he. The first to die had been the one who had carved the Pharaoh's secrets into his back and cursed him with the eternal duty of guardsman, his father. The skin on his back had been flailed off and thrown onto the prone form of Rishid. Ishizu could still see the marks of the initiation ritual on her father's skin despite the bloody cuts from the whip's bite.
Next was Rishid, the one who had tried to kill him so many years ago and could never be trusted again. There had been a flicker in his eyes as he raised the Millennium Rod above Rishid's body, and for a second Ishizu believed that the real Marik would come back, realize what he was doing. That did not happen. The flicker of light disappeared, replaced with the cold darkness that would always accompany Marik's features. Ishizu was already running down the corridor in fear of what her brother had become. The sounds of Rishid's cries for mercy from his master rang out for such a short time before being finally silenced.
That left only Ishizu to take care of. Marik found her scrambling to get up the stairs, the thought of her soul being lost in the realm of darkness inhibiting her ability to function normally. The light of the late afternoon sun from above suddenly made it hard for her to see. Without any hint of kindness, Marik grabbed Ishizu by the scruff of her neck and tossed her up the stairs, onto the sandy ground just inches from the entrance to the crypts below. Her mouth filled with grit, and she lifted her head to spit them out, only to cry out in pain moments later as Marik's foot kept her pinned down to the ground.
Marik knelt down, pressing his knee into the small of Ishizu's back, then lowered his face to her own level. If she could have, Ishizu would have recoiled from the grotesque and twisted look on her brother's visage. Of all the times she had seen Marik upset, this was the worst. This time, his anger had manifested into something else and taken hold of him. She wasn't even completely sure Marik was still inside his own body.
"You," Marik hissed, "are the worst of them all." He dug his knee a little bit more into Ishizu's back, maniacal grin widening at the sound of her short pained gasps.
Despite the pain, Ishizu found enough of a voice to ask, "Why?" even though she was sure that she already knew the answer. So she took every blow without argument, listened dully as the monster with the Millennium Rod described how she had filled Marik's head and heart with false hope, made him believe that his life could be better somehow and that the curse of being forever a tomb keeper would suddenly disappear.
He left her, bruised and battered beyond any point of recognition, as he began his trek through the deserts to exact his revenge on the Pharoah. Not before, of course, stealing the Millennium Necklace away from Ishizu and claiming it as his own. How ironic that he would steal away into the night with the two most well-known symbols of his hated heritage. If she were a bitter woman, she would have laughed. It probably would have hurt like hell anyway.
Is this my undoing? Ishizu thought; having managed to roll onto her back in the hour or so since Marik left, she looked up at the darkening sky as if searching for an answer. Even without the necklace, she could feel the tremors of her actions ripple through an already fragile history. Marik was never meant to leave the tombs. Him and Ishizu and Rishid were meant to live out their lives as guardians of the past. And yet --- nothing was going according to plan. She had lost her brother, and soon she would lose the rest of the world to his righteous fury.
With each shortened breath, Ishizu felt her life slowly come to an end. Feelings of regret and disappointment and sadness rolled around in her gut until it morphed into a pain more unbearable than the beating she had recently endured. There was nothing left for her to do.
Ishizu Ishtar died hours later, eyes open and looking towards the heavens for guidance; the skies over Domino City were just starting to burst into flames.