Komui Lee, supervisor of the Black Order, knew three irrefutable facts. It wasn't like there wasn't anything else that was certain. There were plenty of constants in his life. When Allen Walker, Destroyer of Time, woke up, not wanting dango- that would be the apocalypse. And Miranda would always be apologizing for something or another. But these were three indisputable facts, things that even God in all of His mighty power could never change.
The first- he adored only two people in the world- Lenalee, of course, and surprisingly, Kanda Yuu.
There was no doubt about it; he would die if it meant protecting them. Lenalee was his precious baby sister. When the compatibility of Innocence first caused the Black Order to take her away, he was devastated. Lacking parents, contacts, and the resources needed to retrieve his darling sister, there wasn't anything he could do to save her. So instead he resorted to following the order to her side. It wasn't easy, but with his admittedly brilliant mind, he did find her. And that was where he met the second person he would sacrifice for, Kanda Yuu.
He met him entirely by accident, of course. There was something about the boy that made Komui want to protect him from the moment he first laid eyes on him. The untrusting look in those eyes, the defensive stance- the boy was hardly any older than Lenalee, and scarred deeply.
"What do you want?" He had bitten out scathingly, and Komui was taken aback for a moment. Such a venomous tone from someone so young.
"I'm looking for a girl named Lenalee," he replied honestly. Something in the boy's eyes hardened, and there was something feral, but at the same time protective, deep in that little boy's eyes.
"Why?" was the terse response.
"Because she's my sister, and I've been looking for her forever since she was taken away from me. I've joined the Order so I can protect her to the best of my ability." Komui lets the boy know he is no threat. A moment passes, and then the boy grasps his larger hand and begins to tug him along.
"This is my room. She's in here."
Lenalee is indeed lying on the bed, but considering the files he went through concerning the tests the crueler Order scientist ran on her (which had made his blood boil in rage) she looked relatively peaceful and unscathed. This boy must have been keeping her here, protecting her, for a long time.
"Big brother?" Lenalee murmurs, and Komui immediately goes to her side.
"It's all right now Lenalee, I'm here. I'm so sorry you got taken away in the first place. I couldn't protect you." The guilt comes ever strongly now, and Komui is barely repressing tears.
"It's all right," she softly replies, "Kanda-kun hid me from them. He protected me, big brother. He's so kind."
Hearing this, he turns to the boy in the corner, and smiles gratefully at him. The other flinches away, just barely. It is clear that he is unused to any gentleness, nor any feelings of thanks. Yet, he had still protected his sister when he couldn't. And he hadn't expected anything of it. This child, whether he realizes it or not, is soft and kind on the inside, with a prickly shell- and incredibly selfless.
It is at this moment that he decides that he'll protect this child, too.