He has started from violence, but he will not end with it.
(please note that this is my perception of this character and it might not be the best explained due to me trying to write this for 3 hours well into 2am, but please enjoy)
Everyone in the bat-family and arguably anyone who has become a hero/vigilante goes through drastic changes in their life but Damian experiences so many changes within a short span of time, for 10 years he's been surrounded by only one mind set with only maybe 2 people who had power over him, he was brought up to live with discipline and responsibility. There are other core values and traits that were instilled in him, but all were directed in the wrong direction, it is until at the age of 10 when he is introduced to his father that things get thrown all over the place for him. Staying with Bruce and having to adjust to a different set of rules to the ones he was taught with such rigorous training that it was ingrained into every fiber of his being wasn't an easy adjustment, but he recognised that things worked differently in Gotham city, and he did try to abide, going against his own muscle memory. Damian sees himself as equal to Batman/Bruce but understands that Gotham isn't his area, he is in someone else's home, and he will follow their rules.
It is interactions afterwards that truly change him and it's not a osmosis change it's a conscious awareness from having to follow someone else's rules to acknowledging the rights and wrongs and why there are so and finding ways to fix it. This leads him to end up in a monastery in the Himalayas undergoing a more spiritual growth that helps balance him out, his thinking changes and when he returns slowly his habits, actions and even temper changes. This begins his journey of self-realisation.
Damian cares, even when he was the grandson of the demons head he still cared, he carried a grown soldier to the lazaurus pit just to save his life cause he felt responsible for him, it just gets hidden behind all the quite and reserved parts of him. In the beginning everyone including Bruce and Dick they tried to do normal activities with Damian in hopes of helping him act his age and allow him a childhood he should've had however it made him feel the opposite it is when they give room for Damian to be all parts of himself and guide him through it all that he starts to open up to them.
A true catalyst in his character is his friendship with Jonathan Kent, through the adventures they have gone on together you can see the two really be open with one another, there isn't a politeness or a barrier that states they are simply people who work together. There's banter between the two, room to be critical and make mistakes with the reassurance that when things calm down they'll come back to one another and nothing will change. They understand each other because past all the teasing and sarcasm there is understanding and acceptance.
It allows others to see other sides of Damian when he is with Jon. This is because in the beginning Jon doesn't really know about his past but also after their initial meeting he just accepts Damian, he doesn't really try to make sense of why someone close to his age acts like that but just goes along with it by being himself, he fights back and argues with him but it all ends up water under the bridge for them. When talking to others Jon states and even defends that Damian has gone through so much that he himself couldn't imagine going through, let alone surviving and that others their age couldn't even imagine so instead of judging and fearing or even being put off the more he learns the more he respects Damian.
Damian will probably always be reserved even as he grows but he wont be a shut in or socially inept, he will be content in his life and do as much good as he possibly can. He will enjoy the peace in his quite moments and find bliss spending time with the handful of people he truly sees as family and friends. He's polite and respectful and he understands the responsibilities of the life he has chosen, so when it comes to being the Batman's son he wont be the successor nor feel any right to it. His father is Batman and if someone comes along who he sees fit or maybe they themselves feel like they need to take on that mantle than so be it.
He'll probably find a career as a doctor, whether it be in human or veterinary medicine but being a part time vigilante when Gotham needs him will always be on the table just not a big part of it.
Damian isn't vengeance nor is he unnecessary violence. He is redemption, growth and self-realisation.
Watching the sidekicks or proteges grow was always a heartwarming subject for the league
Talking about how they started out and how they're all maturing into their own heroes is always good and all but the current topic was actively making Batman have an aneurysm.
Sure, there are what can now be considered as funny stories like how Wally recreated the freak accident Flash was in or how Superman felt so bad for how he reacted to seeing Connor for the first time, like how was he supposed to deal with that the kid looked like a younger version of him and he really wasn't mentally prepared after the day he had, even Martian Manhunter joined in with small stories to say about his niece.
God, he prayed they didn't ask him, sure the league knew about Dick and his story, but they didn't know all the details in the beginning and still don't know about any of the others.
How on earth was he supposed to explain it all.
Every single one of Bruce's kids has willingly walked into that situation and there was nothing he could really do about it, yes as a legal guardian he could ground them but when dealing with these kids in specific it wouldn't have held up for long before they started testing the limits.
Sure Dick was the first and everyone soon understood the kid wasn't exactly normal, but they all saw him as the smiley kid who was just really energetic and bouncy. How on earth does he explain that the kid was thinking of straight up murder that he's almost glad he found the batcave and he could steer him away from that thought early on.
Barbara Gordon just showed up one day, or night with her own costume and refused to back down, in a similar fashion Stephanie Brown did the same so many years down the line, she found out her dad was a criminal, clue master to be exact and decided to take it upon herself to sabotage ever. single. one. of his plans. She wasn't robin long but soon became Spoiler and hasn't left.
When he caught Jason stealing the tires off the batmobile he decided to switch him to a different school to which ended up being a front for crime that the kid decided to expose all on his own and again showed no signs of backing down, so he took him in and made him undergo 6 months of training before stepping out as robin.
Tim, he didn't want to start on, Tim found him in his own dumpster and forced Batman to take him in as robin, that's actually putting it nicely, Timothy Jackson Drake didn't give him an option, just a reality, that kid is too smart for his own good and now he was a vigilante that he had some control over but he swears that Tim is some kind of mastermind but there's no proof, the decline in major crime organisations activity is a joint effort from him and Jason, and he has a feeling that the league of assassins hasn't caused trouble not because of guilt for Jason but because Tim did something .
Duke was older and a metahuman who was starting to go down the route of becoming a vigilante that Bruce just trained him and he became Signal.
Damian is his biological son and honestly as much of it was a shock, taking in another kid at this point was like clock work, except his youngest to no fault of his own was just as much of a loose canon and a more outwardly dangerous one at that. It took a while for the boy to calm down and to help him settle into some kind of normalcy but it happened, he's just a little rough around the edges more so than the others.
Cass was in a similar situation but approached Gotham and after saving Commissioner Gordan Bruce decides to take her in to help steer her a brighter path than just being a living weapon the only difference is that Cass made that choice herself while Damian felt like he was in a place that didn't understand him.
But what started out as two kids that he had to make sure wouldn't get hurt slowly turned into more. Easy right, just make sure they don't do anything stupid/dangerous/why did you think that was a good idea? Cause who in their right mind would go against THE Batman. His kids would, doesn't matter if they were adopted or not but they would and feel no remorse for the numerous grey hairs and mini heart attacks they've given him.
Don't get him wrong he loved them, but the league didn't know the half of it, and he really didn't want to open that can of worm because he wasn't ready for the questions that came along with it, cause being honest he really didn't know the answers and stopped trying to find them for his own sanity's sake.
How does he explain this to the other heroes. Sure, they all know what Gotham city is like and how it's somewhat become a crime alley due to issues here and there but like its being fixed and it's come a long way so it can't be that bad. I mean you don't see this happening in any of the other cities like it's circumstantial because some kid got powers and now you help them with it and stuff, as the other heroes have done but these kids- these kids were something else, like he did try to stop them you know, have them live normal lives and not care about anything else or take on the stress of crime fighting but they wouldn't listen. In fact, Bruce Wayne was willing to bet his entire wealth and everything he was that if he had just stood by and had done nothing, these kids still would've found a way to fight crime, even if it meant taking a more difficult way to do so.
I'd like to apologise if there's anything in this that doesn't align with the canon stories but a lot of this is from my own headcanons and I just wanted to write something soft for Damian that would pin point not just how much I think he cares for his family but how he does so and his journey in feeling loved by them.
Damian was and still is stoic, witty, and sarcastic he'd often lead with logic in mind and his morals and ethics close by. He knew he could be temperamental, and almost everyone he met for a small time would say he was made of stone and annoying. He knew this, and if he could choose, he probably would've preferred to stay that way. At least to the outside world.
He was just a boy when he arrived at the manor, no older than 10, morals and life more skewed than he truly knew. He stayed in the manor, with the people he judged to be "inefficient", he slowly smiled, laughed and cried even if it was silent and where he thought no one would know.
He slowly became a boy he was allowed- meant to be, in the most Damian Wayne way possible. He brought home pets, and it started out fine from cats and dogs. The cow was a bit odd, but then Goliath happened, and Bruce was more than tired to argue. He remembers his father's tired hand over his face, thumb, and index finger on the boned arch of his eyes and a cup in the other hand, but he didn't miss the smile, that left him in awe and the look in his eyes afterwards was soft and gentle. That was the first instance where he felt the warm feeling in his chest.
Damian was 10 and a half when he remembered coming across lego, it wasn't much, but it was a small set that Dick had never opened, and he got curious. He built the structure, sitting at his desk late at night. Sometimes, the parts wouldn't quite fit, which was to be expected from mass-produced products. It was a week later when the manor was empty that he left and came back home, almost running straight to his room. Bruce came home expecting to find everywhere based on the transaction he saw, but instead, it was quiet. He had asked the rest of the kids if they had seen something or known about anything regarding the lego purchases. That night, he went for patrol, asking Damian if he'd like to join, and for the first time, he'd said no, walking away calmly. A few days later, Bruce walked into his sons room, concerned in the change of behaviour, only to see a lego city built on the floor, his bed was moved to the side like the rest of his furniture. He had created different parts of different cities and connected them, but at the centre was Wayne manor, his home. The city was later moved into a vacant study, where more sturcture had shown up. Bruce often took photos to show Clark like he did with every other kid of his, adding them to a secured hard drive of photos and video of all of them including things from Cass and Dick's perfomances, Jason working on a car for the first time to Tim going on about his long winded rant about 'how to get on buzzfeed unsolved' and more. Damian had found these photos and videos and watched every single one and reading the little descriptions attached to them, he teared up at it but never spoke about it only to make sure he'd look his best when he suspects his father would take another photo.
Damian remembers his 11th birthday, he had spent the entire day avoiding everyone and he almost succeeded. Dick had found him, he was sure he'd drag him to some celebration and he was sorta right. He had been dragged to the kitchen where he had found Steph arguing with Jason about decorations, Barbara tried to get them to stop but soon gave up while Duke and Cass helped Alfred, who was decorating the cake and prepping food. Tim was busy making hot chocolate for everyone. Bruce had shown up beside him, placing a hand over his shoulder. Even though Damian said this was unnecessary, they all saw the glaze over his eyes and the way they lit up slightly. He was truly grateful for that day. He felt loved and normal even for a few seconds. This was the second time he had noted the warm feeling in him, stronger this time and more intense.
He was 12 when he had gotten into an argument with Tim, and it hadn't ended well. The two had always argued, the family knew, but this time it was really bad that even Jason refused to brush it off. Everyone was worried. Tim had gone about grumbling, clearly agitated, and Damian looked unfazed. Tim had up and left the manor going to the teen titans to cool his head, and Damian had taken it as an opportunity, giving himself a deadline.
Tim had come home one night, everyone was probably asleep or not even in the manor. He had walked into the manor and found a yellow folder on his desk with no creases in its paper form and a wax seal holding shut where the little rope would wrap around the circle. A single white tulip was placed beside it. The contents of the folder was a stack of papers explaining the tulip and its symbolization followed by a lengthy apology going into depth how wrong he was for saying the things that should never have been said and Tim read the entire thing, at the end was a small card that he later put into the case of his phone. "Fact: historically, stars and constellation hold multiple meanings and purposes from division of labour to guiding us to different locations. These stars have also helped guide families to one another in stories, and it seems plausible"
That card was kept safe, and Tim couldn't help the small laugh that crept up. Who knew his little brother could be so corny in his own way. He made it a point to make small card explaining the white tulip he left on Damian's desk.
He was a teen when he died, and he had come back roaring. When everything settled down, he lay awake at night, his death and resurrection repeating in his brain, and in front of his eyes. yet it didn't bother him as much. He had snuck out that night going to a safe house hoping to find someone only to end up going in a full circle. Damian didn't cry. He was only allowed to express himself a few years ago, and he didn't want to cry. He made it a point not to get too emotional, but he couldn't look the man in the eyes. He slowly rested his head on the others abdomen and slipped his hand into the others. Jason had ruffled his hair before lifting him and taking him back to bed. Damian curled up under the blanket and wouldn't let go of him like he'd disappear. Damian continued to mutter apologies under his breath until he finally dozed off. Jason had given him his number. If he ever needed to talk and he did call, he asked if he was ok. Anytime a joke or taunt was made about Jason's experience, he would leave a threat in their rooms.
Damian was almost 14 when he found out all his brothers' trauma and fear linked to the infamous clown of Gotham city. It wasn't something they told him, rather something he picked up, and when he did his own investigation, Damian felt a part of him awaken that he long thought gone. Whenever the clown showed any sign of himself, Damian knew, he tracked everything, he may have even missed a few classes and an assessment, but that was swept under the rug due to his stellar record. Damian had taken it upon himself to delay the alert to his father when he went and took care of the clown himself. When Batman had arrived at the scene, Joker was already being hauled into the van willingly being sent to arkham. Later that week, he received a call saying Joker hadn't left his cell, nor had he acted out. This news of joker staying in the asylum willingly after a fight with the recent robin had spread like wildfire and when it landed in the ears of the rest of his family, he denied everything and they couldn't say anything cause how could they have been sure when even joker wouldn't open his mouth. Not even about the disturbing threats that had started showing up in his solitary confinement cell.
In a dark part of his life, Talia had shown up again in his life, and while he still recognised her as his mother, there was a pit in his stomach that wouldn't let up. He was aware how his mother was raised and that her changing may be difficult, but the pit kept growing until he could no longer ignore it. The first person to see all this was Alfred, who simply held him close and didn't let him go knowing there were no words he could say that would help. Bruce had been informed and had talked to Talia to keep her distance from him. It wasn't hard for the kids to realise something was wrong with one another, knowing each others behaviours. They all kept close, and it was one thing that had pulled him back together.
"If for some reason you start thinking your mother or grandfather would be disappointed, know that we would be proud of you"
Damian had never like nicknames not for himself or others, if someone called another by one he couldn't care but when Barbara called him 'Little D' he let it slide however when Tim had called him Dami he had gotten all flustered and simply went to his room. Later upon further questioning it was revealed that the nickname Dami could be linked to the saying of 'my blood' and that in arabic poetry it was common to call dear ones by names of body organs because without them you wouldn't be alive. to love was to be close to death. (If I'm wrong please let me know I'll fix this) They still called him Dami but if anyone else did the rest of the family would stop them because Damian Wayne was their blood, even if none of them weren't related he would always be their blood and in turn he'd call them his blood, his lungs, his heart and if anyone were to harm them he'd take it as a threat to his own life; which everyone in Gotham knew would not be taken lightly.
It was moments like this that allowed him to achieve the impossible and would make Damian shiver with warmth, he would never admit to being afraid and maybe there was a time where he wasn't, wasn't afraid of anything but now he had something to lose and it made him feel human. Though he doubts he had much to worry about, try and hurt them and see what happens.