Your assessment of the construction of Gren as character? Actually amazing, I love to find people over here thinking thoroughly what the storyline wants to portray.
I will say tho about the reaction towards Gren's death, it can be also be seen by the politics of the reader, I have read also the self righteous comments about his death, of how he didn't know any better, and we should feel emotionally compelled by his death, it's a baby talk towards addicts and mentally unstable people, they erase their autonomy from them and infantilize them as people without any other choice, is a well intended impulse for I am of the political stance that justice must be restorative and reformative, I hold value in Gren's humanity, I understand where he comes from but that doesn't mean I will excuse his actions, two things can be true at once, I can see him as human being, not a machiavellian caricature, and also say that he was not good news for Shin, and his death whilst not being something that elates me (because again, I don't think death is justice) I can for sure say that this is not the kind of story to have a jilly jolly end for him on it's books, it's gonna be crude and his death in real world it will have happened way earlier, because in the society that he lived is not one to be forgiving.
For the people that we're actually happy about it, maybe they also need to check on their biases and dehumanization of addicted impoverished bodies, after all Gren it's the result of a system that crushes you onto it's lines, he as a orphan child, impoverished and mentally traumatised was set from the very beginning for failure and was sentenced from his first jail time, because jails only repeat the cycle of violence and perpetuates it. Not even Shin with his unbreakable will to survive, can escape it, when we met him he is barely making ends meet, and is only by the hand of someone who holds power that he finally gets a semblance of stability and still that doesn't take off the fact that the moment that he scapes Jake protection he is as disenfranchised as he always has been. Gren's death was just the most probable outcome of his life.
amso remember that chapter where a random junkie in the rehab house offered him some pills so he could "get better" and therefore get out of there and meet Shin. He convinced Gren, who took them "off camera" and since that point he seemed to be getting better and his hands stopped shaking. He was lying about getting over his drug addiction.
Good call out. I completely forgot that happened. He was definitely still taking something.
I've skimmed through the newer comments and especially the ones right after the last chapter dropped, finding a lot of opinions on the Character Gren, some even stating that he was getting better; that he was Shin's only chance at a family; that they didn't even care he died.
Now, unlike popular beliefs, storytelling doesn't only happen when characters tell you how they think or feel. In fact, it happens all the time - every move a character makes, every step they take, every decision that is made within a story tells volumes about the characters' thoughts and values. Therefore, just telling in narration or having a character in story tell you straight away that something is this way or that means little in the broader scheme of things, if what is shown differs from it. Words mean nothing.
Take that as a base of this assessment, and let's try to understand who "Grens Heim" as a character was and what he meant to the overall story, especially regarding his supposed future life with Shin as his family.
We open up their relationship with Shin vaguely recognizing a similarity between Owen, the kid from the Garage, and some kid he had known from his own childhood, whom he hadn't thought of in a long time and had almost forgotten about. We get that scene for narrative reasons, in order for us to get a clue about Gren even existing, but it also sets in stone that he had a certain amount of affection for him, but not enough for him to look for, or even really think about him in the last decade or so. He barely remembered his face upon seeing someone who looked extremely similar.
On Gren's side, he recognized Shin on the spot, because he had kept their old picture together and would look at it the way a religious men might look at the bible. He held it and remembered a time in which he had it rough, yet it was still bearable. One of the most important differences was that back then, he had someone he was allowed to call "brother", someone who gave him strength by protecting him und caring for him.
This person is now gone, but the memory lasts, which has been the only thing that kept him going in his wretched life. Like the woman they had met as children, telling them the drugs were the only thing that gave her any happiness anymore. Keep that in mind.
So now they have met again and Gren immediately lights up, but shows signs of being uncomfortable with a guy like Jake, for example. Sure, he knows him as a dangerous crook, but the problem is that Gren, as a member of MASS, knows better than anyone that it would lead them to two different frontlines, if Shin were to collaborate with Jake from the Mercifuls. He's afraid that Shin wouldn't take his side, when Shin isn't part of any of this himself and losing it over something so childish, again, just endangered Shin again.
Just to cover that side as well: If he actually were just worried about Jake being a crook, it would even reflect worse on Gren, because he's a far more dangerous crook to be around than Jake, because Gren is not in control of himself at all and gets himself in a lot more trouble than Jake does. This isn't made completely clear, but it's very likely it's the former reason, aside from simply hating the fact that he's obviously "close" to Jake.
Alas, we come to the point where Shin realizes that Gren could be in trouble and worries, and the sequence of Gren "getting better" for Shin in rehab. Those sequences shine light on the affection they hold for each other and the nature of said affection.
When Shin left his old life behind and tried to reach a point which can be called "living", he forgot all about the "younger brother" he had found along the way. They weren't together for many years, as even their latest memories show little sign of aging when held against their earliest memories. That doesn't mean Shin didn't have any brotherly feelings toward Gren, but they weren't that deep.
Leaving him behind may not have been an easy choice to make, but he decided to make it anyway. He never looked for him even years after the fact. Remember, he has a friend that can easily look into people; Ho-Sung found out about Gren's history after they randomly met him on the street. Shin would have had ALL the reasons, yet he gave no shit about this kid he once knew. That breeds guilt. He finally met the kid again and finds out he never stopped thinking about him, while he clearly didn't think about him at all.
He now wants to make right on his promise to protect him; to be his "Hyung". Which is why this kid he barely remembered the face of is suddenly important enough for him to pick up the gun Jake left him and point it at another human being. He wants to help him now... but it's already too late.
Too late? Even though they are totally "family" and he got so much better? Well, remember that moment with the lady and her "only happiness" again, as I said I would come back to it.
While Shin took this advice as a cautionary tale, refusing to ever take any drugs harder than tobacco or alcohol, Gren fell into the same trappings as the woman herself. Holding onto his memory of a better time, which was far out of reach, he might have dreamed himself a new reality, falling deeper and deeper into his addiction. Gren is shown to be impatient, irrational and lacking any sense of tact or self control. Someone like that doesn't easily let go of an addiction, because they don't have the diligence to stay clean, demonstrated very well during the time he had to get a fix while one highly influential Gang in the city was looking to capture and ultimately kill him.
Suddenly, he can stop taking drugs, because Shin is there? Yes, because Shin is just another drug to him - a distant dream, reminding him of better times; the only thing he ever had to hold onto. Not so much a brother, than simply his symbol of something he never had: Happiness.
Let me make this clear: His obsessive behavior shows distinctively that he never got "better" - he simply switched out one addiction; one crutch for another. That also means he would likely fall off the wagon again at the drop of a hat - the moment Shin does something that goes against his view of what his imaginary brother was or should be, he might have a breakdown, just like Shin being close to Jake, his "enemy", was enough for him to snap and shoot him.
Not to mention the fact that he would have never survived another time in prison, because he would have taken his own life first. But nothing but that was on the horizon for him. Last time, in fear of going to prison, he killed a bunch of people in cold blood. Not that I say killing should never be the answer among crooks, but I'm saying he's a bit different from Jake: Again, Gren has no control over his actions at all, while Jake does. That and the fact that Jake isn't actually crook make this difference to important.
They aren't their "only chance at family" or even "real family". They are each other's IDEA of what family is. A placeholder, polished by memories seen through rose-tinted glasses.
Gren was the one who wanted to see Shin so bad, he couldn't understand that it was too dangerous because of him in the first place. He wouldn't accept a no and Shin, who felt bad for him, gave in. The collective IQ in this situation made onions cry, but let's overlook it as an act of desperation on both ends, which cost them dearly.
The thing is, I'm probably one of those people that are referenced when another comment says "people say it was good that he died" in utter horror. But think about just a bit further than simply "poor Gren", and think about the implications of how his life, with everything stated above, would have actually continued. He isn't like Shin, who had a few encounters that brought him down, yet would do well in a regular, calm lifestyle, doing a good job and living properly. He just had to be given a chance.
Gren was given a chance, but he didn't take it. He couldn't because he needed to see Shin, even when everything told him it was a terrible idea, becasue there's dangerous people looking for him. Even when Jake made it clear to him that he would get his "Hyung" in trouble as well. He didn't take drugs in rehab, but that's why he obsessed even more over Shin.
If I were to make an equation between the two: The reason Shin was able to make it out and Gren didn't is a telltale sign of their innate characteristics. As Jake mused once, if two mice were thrown in a bucket of cream, one would swim until it all becomes butter to escape. My own version would involve the proverb "If god hands you lemons, make some lemonade" - Shin would make the lemonade (and probably open up shop with it, lol), while Gren would bite it with little effort, huff the cest fumes and imagine it was lemonade, while sucking pure acid (no shade on lemons, though).
He says he loves him and I'm sure he did, but what he really loved was what he imagined him to be; the idea of him being his brother. He barely even knew the guy, beyond him liking cars. It's the same the other way around.
Those two were poison to each other and Gren was destined to either go to jail or die in some way or another. If he was a dog, he would have been put down ages ago and it would have been mercy. Don't delude yourself into thinking this character could have had a redemption - his death and the sacrifice he made were his redemption, there was nothing beyond that.
Also, for those who said they got over his death too rapidly: Don't you think it takes time to bury a corpse, likely covertly as well? Do you know how long it takes to get a gravestone ready? Those things need to be carved, they don't stand around with all the data on them, ready for pick-up. Time has definitely gone by in the shot that continues after his death. And I have no reason to believe that Shin, who's also callous due to his past, would wallow in endless sorrow over a brother hadn't seen in over a decade, barely remembered and spoke all of 50 minutes in total to. That's exactly what I meant before: he had no impact on Shin's life, barring the additional trouble he helped him get into, so there really is nothing to miss. Just a few weeks prior, he couldn't even know if he wasn't already dead.
I'm not saying he isn't sad. He finally wanted to make good on his promise to take him under his wing and be his brother, but he couldn't safe him at all and now he's gone. But for Gren, this was the only way he could ever be rid of his misery and he would have caused trouble for Shin down the road again, with his antics, so it is better for him as well.