It’s instructive for writing decent fiction, so I’ll put my longform blog-like thoughts here on what they did right compared to most fiction I’ve seen recently, which could be useful to someone whether or not they’ve seen the show. It’ll have major spoilers though.
Silco Villain Analysis:
Silco is first shown as a tropey crime lord. He’s cruel, power-hungry, and has a damaged eye and a scar. His philosophy is that power is held not by those who are born with it, but by those who will do anything to take it.
But then we see his backstory. Silco grew up in the undercity, in a literal fissure in the ground where the air and water are polluted by the rich city state Pilthover that rules over them and literally sits above them. As he became a leader of the undercity, he fought for its sovereign independence from Pilthover, including to the point of promoting violent uprisings. He was then betrayed by his best friend and co-leader Vander, since Vander decided to make peace with Pilthover so that the warring and violence would stop. Basically, Vander had less of a stomach for the violence after seeing so much of it, whereas Silco remained radical for his goal of independence. And so Vander tried to kill Silco to make peace. And then Silco, while he was being betrayed, cut, and drowned, narrated that he could just die and have his troubles go away, or he could fight with everything he had, and he did the latter and managed to escape death. As Vander ruled the undercity in peace (but still oppressed and polluted by Pilthover), Silco partnered with a scientist that was making a new weapon: a mutant serum called shimmer.
Years later in the show, Silco used the power of shimmer to overthrew Vander and become the boss of the undercity. Unlike many cliché villains, Silco respects Vander, had gotten over his hatred for Vander for betraying him, and is even thankful for Vander’s betrayal since he views the life or death moment as having helped him find the strength that he was previously lacking, but he wants to go on his more dangerous path of gaining independence for the undercity, which means replacing Vander. And that’s where his villainous streak gets bad: he’s willing to kill Vander, and even Vander’s adopted children to eliminate witnesses when they try to rescue Vander. The youngest child, however, embraces him, and so instead he adopts her as his daughter and truly cares for her, but by doing so corrupts her to be more like him as she becomes an adult.
Throughout the show after that, he makes plans, sometimes has to adjust those plans based on new things happening, reads other peoples’ emotions very well and communicates to them effectively to move forward with his goals, etc. He uses intimidation, science, and economics where possible, and violence more rarely as needed. There are no bad plot arcs based on obvious miscommunications and so forth. He’s a dynamic, competent, and realistic character that is impacting and reacting to the plot. He focuses on the development of shimmer to grow his undercity’s power so that if or when war for independence breaks out, his side will have a chance against Pilthover.
But then, toward the end… as the situation gets messier, he chooses a path of peace with Pilthover while getting what he wants. His years of production of shimmer along with his adopted daughter’s theft of Pilthover’s key technology enhanced the underworld’s power enough that the council leadership of Pilthover agreed to let the undercity have its independence. Silco proposes to cease the production of shimmer and give back Pilthover’s stolen tech, thereby depowering himself in exchange for everything he has ever wanted: sovereign independence for his undercity which will be called Zaun, along with trade and economic deals between Zaun and Pilthover. And now he understands the late Vander better. Politics over violence.
But then Pilthover gives Silco a curveball- he has to give up his adopted daughter to be arrested for her crimes as part of the peace deal, which he contemplates doing and is leaning toward doing, but is torn up about it. He ends up being killed by his adopted daughter, and loving her anyway as he dies, siding with her at the end.
A tragic ending for him, but he’s at peace with it. Similar to how he views Vander’s betrayal of him all those years ago as having helped him find his own strength, power, and agency, Silco views that he has now passed on those traits to his adopted daughter.
Jinx Villain Analysis:
In League of Legends, Jinx is basically a Harley Quinn knock-off. Little depth. That’s what the show had to work with, and they filled it in so that she’s a better character than recent depictions of Harley. There are so many ways to mess this trope up and they avoided most of them.
Jinx starts off as an impoverished kid thief from the undercity; a physically weak tinkerer trying to make little smoke bombs and stuff to help her older sister and her two adopted brothers. Her parents were killed by Pilthover’s soldiers/police in a failed uprising, and so she is raised by Vander, who doesn’t have much in common with her and instead focuses on raising Jinx’s older sister who he has a lot in common with. And so Jinx ultimately is raised mainly by her older sister, which is who she has her primary emotional bond with. Her adopted brothers view her as weak, and it’s always her sister that sticks up for her.
In an attempt to help her sister and adopted brothers save Vander from Silco’s overthrow of Vander and prove she is not weak, Jinx accidentally messes everything up. One of her creations, a bomb, accidentally kills her adopted brothers directly and ultimately leads to Vander’s death indirectly. And then from her perspective, she is abandoned by her older sister due to her disastrous bomb decision, and so instead Jinx embraces Silco and joins him. Silco replaces Jinx’s sister as the one directly raising Jinx, and for whom Jinx has her main emotional bond with as her father figure.
When she grows up, Jinx becomes a mentally unwell weapon maker and combatant, supporting Silco’s undercity’s accumulation of power against both Pilthover and rival gangs.
Harley Quinn’s “craziness” as depicted in Suicide Squad movies and so forth, is pretty shallow. It’s played most of the time for humor and aesthetics, and if one were to describe in what specific ways she is crazy, it would be hard for many to do so. It does have a name though: it's called histrionic personality disorder, and in her case it's combined with what is basically sociopathy I guess.
Jinx’s mentally ill aspects are more specific. And she suffers for it; it’s not depicted as funny. The two adopted brothers she accidentally killed are now voices in her head and visions in her eyes. She is emotionally stunted, stuck with the personality of a child despite possessing the intelligence of an adult engineer and schemer. She is emotionally over-dependent, first on her older sister and then on Silco as her adopted father. She is obsessive-compulsive, which makes her a good engineer and schemer but also stresses her mentally. She is self-absorbed. She lacks empathy for others except those she latches onto. As her sister returns after seven years, Jinx is forced to confront the violent person she has become, and has an identity crisis over it. She wonders if she could go back to being a more normal person after all that she’s done, accepted by society, or if should she remain in her more violent line of work of empowering Silco and the undercity.
Despite her mental issues, she’s among the most proactive and competent characters in the season and all of her actions combine into a specific purpose rather than being random. She builds a variety of dangerous weapons and traps. She uses them to kill rival gang members that try to attack Silco’s shimmer operations. In a world where Pilthover’s soldiers/police killed her parents and most of them are corrupt, Jinx kills soldiers with bombs in order to sneak into Pilthover’s academy to steal a sample of their most powerful technology, successfully reverse-engineers it, and makes it into a powerful new weapon to potentially use against them. When her sister returns after seven years and Silco is hiding that fact from her, Jinx correctly senses something is being hidden due to Silco’s gang acting differently, captures and interrogates Silco’s underboss in order to find out that her sister is back, leaves that underboss unharmed, and then actively reaches out to her sister to try to reconnect with her. She is angry at Silco for lying to her but goes to him to learn why he did, and is convinced to remain on his side. When Pilthover’s technology is stolen back from her, she goes after it, kills more corrupt soldiers to do so, fights one of her childhood friends who leads a rival gang now, and successfully retrieves it before it gets back to Pilthover, nearly dying in the process and then going through an agonizing recovery.
So she’s not quite sociopathic up to that point- she mercilessly kills those who she sees as enemy combatants rather than civilians, and for specific goals. She has outright schizophrenia and a growing identity crisis, but mostly functions around it. It's not the "tragic backstory therefore I kill everyone" weak trope.
But then that’s where her mental illness starts to go off the rails and screw everything up for everyone. Her sister gets a girlfriend who is a Pilthover soldier (who wants to get Pilthover’s stolen technology back from Jinx), and Jinx views that girlfriend, of the enemy side, as having replaced Jinx as her sister’s closest emotional bond, and Jinx visibly sees schizophrenic delusions of that girlfriend laughing at her. She is given shimmer serum by Silco to save her life from injuries at one point, which makes her stronger but likely deteriorates her mental state further. And then, as Silco agrees to peace with Pilthover, Pilthover’s leaders demand that Jinx be given to them and imprisoned as part of the deal, putting Silco in a tough position to choose between the undercity’s peaceful independence or his adopted daughter’s freedom. So Jinx feels betrayed by both her sister and by Silco. She successfully captures Silco, her sister, and her sister’s girlfriend, to talk to them and figure out what her decisions will be. Mainly at that point she wants her sister to side back with her.
In the end, she kills Silco to prevent him from killing her sister, and spares the life of her sister’s girlfriend when she could have killed her. As Silco dies (which Jinx is heartbroken over), he tells Jinx he would never have gone through with giving her over to Pilthover, would give up everything else for her, and tells her to be herself.
She then resolves her identity crisis, and decides to fully embrace herself as a war criminal against Pilthover, remembering what Silco told her years ago: “we will show them all”. She could turn herself in to Pilthover for life imprisonment in terrible conditions in exchange for her undercity’s peaceful independence, but she chooses not to make that type of sacrifice. Instead, she chooses to “show them all”, and launches that new weapon, which she made from the tech she stole from Pilthover, straight at Pilthover’s council chamber, killing most or all of Pilthover’s seven corrupt council leaders and triggering outright war for the undercity's independence.
And that’s an actual set of character arcs for villains. One can see from their perspective why they're the protagonist of their own stories.
And a chain of cause-and-effect actions went from the economic and cultural situation of Pilthover and its undercity, to Silco, and then to Jinx, and then disastrously back to Pilthover’s leaders, with certain decision points along the way to either continue the cycle or break it with a more selfless decision.