Nayuta

In the view of most Citadel members, Nayuta and two other members of Destroyer, Dustin and Sommer, are a family. The trio may not be related by blood, but everyone has tacitly acknowledged the existence of this special family.
However, Nayuta doesn't appear to agree with this saying, not because he has anything against the other two members but rather, it is precisely because he genuinely cherishes them that he finds this conflicting. From his perspective, with such an unconscionable past, there is no way he can wash away the blood on his hands or get rid of his dark side. So, how could he deserve to have such an intimate bond with those two wonderful persons?
But here comes the dilemma. Even though Nayuta truly believes his existence is akin to the weeds growing in this beautiful greenhouse, deep down in his heart, he longs for nothing more than the warmth of this non-biological family.
Actions speak louder than words. Regardless if it is when he's able to listen attentively to Dustin's teachings and offer Dustin a helping hand or his thoughtful care of Sommer and constant assistance and consideration of her in life... they all make it obvious that Nayuta has long been treating the two like family.
There's no doubt that his "father" and "sister" will patiently await the day he finally makes peace with himself.

"This is the target of your mission."
The black-haired young man glances at the photograph indifferently and nods.
"Per usual, do a clean job. You've been doing great, Ten."
The four words "do a clean job" have long been imprinted in his mind. No compliment or reprimand from the other party can stir any emotion within him. In actuality, he has a name, but everyone is addressed only by code numbers here. Perhaps it won't be long before he eventually forgets his own name, forgets his time spent in the orphanage, and fully turns into a number, a life-taking puppet.
Like all of his previous missions, the young man sneaks into the room where the target is playing a game with his young daughter, so immersed in joy that he's totally oblivious of the murderous intent heading his way.
There is no better opportunity than now. First, deal with the target, then get rid of the daughter and escape via the planned route. It won't even take ten minutes in total.
The gun barrel is now pointed at the typically solemn man, who is currently going all out to make funny faces just to make his daughter laugh. She chuckles and jumps into her father's arms.
At this moment, a thought suddenly strikes the young man. He seems to have had gentle parents, though his memory is already hazy, as well as a cheerful playmate who would laugh with him despite them being in the rundown orphanage. Most importantly, he has his own name. His name is... Nayuta.
The young man pulls the trigger, and practically in the blink of an eye, shrieks, cries, and commotions erupt concurrently. The bodyguards rush into the room, and the familiar pain of being shot radiates through the young man's body.
As it turns out, his bullet missed the target, rendering the mission a failure.

Nayuta still vividly remembers that after he awoke from falling unconscious during the escape, the first person that came to his view was an unknown teenage girl. Her abnormal arm immediately caught his attention, but upon sensing his gaze, she hid her hand behind her a little uncomfortably.
"H-How are you feeling...? I treated your wounds, but I'm not too good at bandaging..."
Nayuta glimpsed at the slanted knot on the gauze and the cautious girl. "Thanks," he blurted out.
Even he himself was stunned when that word escaped his throat, for it seemed like forever since he last said it, and yet it came out so naturally.
Subsequently, he learned that the girl who saved him was called Sommer, and he was temporarily safe since he was lucky enough to be taken in by the Citadel. Still, he was already a traitor in his organization; he knew he couldn't implicate his savior. Just like that, he attempted to leave, had his wounds worsen, and was forced back to treatment multiple times by Sommer's father, Dustin, until he finally recovered.
Then came the day for Nayuta's bandage to be removed. He observed the interaction between Sommer and Dustin. After the time they had spent together, he knew that even though the two of them looked bizarre, they were simply an ordinary, loving pair of father and daughter. Such great people weren't supposed to have entered Nayuta's life.
Dustin could heal Nayuta's wounds but not the young man's old scars. It wasn't hard for Dustin to guess what Nayuta could've experienced thus far, nor did the tinge of humanity deep within the latter's indifferent eyes escape the former.
"If you can't be the light for yourself, then try being the light for someone else," said Dustin to Nayuta. This was the chance Nayuta, member of Destroyer, got to join Source Citadel.