A character trait is later recontextualized into something bad/tragic, it's always been there, we just never paid attention

[u/RedNUGGETLORD]

Deku's self sacrifice - My Hero Academia

Initially portrayed as purely heroic, it's later shown to be extremely detrimental when he refuses any aid from his friends, abandoning them to "protect them"(of course, leaving them also puts them in danger since he can no longer be there to save them if something goes wrong

The same quality that makes him a great hero, also leads him to nearly lose everything and get EVERYONE killed(since if this tired, weakened Deku did encounter AFO/Shigaraki, he would almost certainly die and have his powers taken)

Seiya Ryuuguuin's cautiousness - Overly Cautious Hero

The whole series is about how the main character is prepared for any circumstance to an insane degree(being the highest level half-way through, perfectly predicting that an ally would betray them through ridiculous jumps in logic, etc)

It turns out that the reason for this was that in a past life(unknown to him) he was extremely easy-going and unprepared for everything, always winning due to luck and skill, however, one day he ends up losing due to not finding out about a bosses weakness, this leads to the demon king murdering his friend, eating his Goddess, and then devouring his girlfriend and the child inside of her right in front of him. The Demon King then takes over the world and basically turns it into Berserk on steroids

Erens entire character - Attack on Titan

He hates the titans not because of what they've done(though that's a part of it), but because they've stolen his freedom, so when he learns that in reality, the Marleyans are the true enemies, the ones who have taken his and everyone elses freedom away, he does exactly what he said he was going to do, just to a different enemy

Erens philosophy is that anyone that tries to take his freedom deserves to have theirs taken away, Zeke becomes a slave because he tried to take away the Eldians ability to breed, the Marleyans lose the freedom of living because they tried to take his, it's always been a core character trait, but when he becomes to antagonist of the story in the last parts, this character trait of his is front and center

[u/Fayde_Away]

Ace Combat Zero: Larry 'Pixy' Foulke - Questioning Authority

Your wingman through the majority of the game, Pixy is a cocky but seemingly decent guy who, at several points in the campaign, as you are given increasingly illegal or immoral orders by command, either questions the reasoning behind them or refuses them outright. You know, like you're technically supposed to do as any soldier asked to carry out unjust orders like bombing civilian targets with no tactical value. You genuinely can see him at times as a moral compass.

Which is why it smacks you in the face when, after seven nuclear weapons are detonated beneath where you're flying, breaking comms with command and scattering IFF, Pixy just laughs, says he's finally found a reason to fight, and tries to shoot you down.

When you eventually face him as the final boss, you realize he's questioned his country so much that he's abandoned the idea of nations altogether, believing the only true means of bringing peace is destroying the notion of borders. With nukes. A lot of nukes.

[u/vp917 → u/Fayde_Away]

Also from the melodramatic war crime plane game genre, we have the mirror opposite with Project Wingman's Crimson One, who's fatal flaw is his complete inability to question authority. At the start of the game, he's widely regarded as THE best pilot in the world, leader of the elite "Peacekeeper" squadron tasked with protecting and enforcing the Pacific Federation's rule over his native homeland of Cascadia. But when the Cascadians decide to secede from the Federation, his unshakable belief in the undisputed righteousness of the Federation leads him to remain a loyalist and wage war against his homeland's bid for independence, which leads to him going up against the player character "Monarch" (a mercenary pilots hired by the Cascadians) and getting his ass kicked, just one of their string of overwhelming victories that turns the tide of the war so sharply in Cascadia's favor that the Peacekeepers themselves lose their shit and commit fratricide just to launch an indiscriminate McGuffinite turbonuke saturation bombardment of a major Cascadian city, which hits so hard it unintentionally triggers a Pacific-wide geothermal apocalypse.

But instead of taking this as the cue to switch sides and fight back against the deranged Federation radicals that devastated his homeland, he blames the whole thing on Monarch for "denying the Federation peace" and forcing them to escalate. His projection gets so severe that when the war is about to end, with the Cascadian capitol of Presidia all but liberated and the last Federation holdouts declaring their intent to surrender, he shows up in an experimental superfighter and firebombs the whole fucking city with turbonukes, wiping out the Cascadian forces, the Federation troops, the capitol of his own homeland. And then he spends the next 10 minutes yapping about how "You, solely, are responsible for this" while spamming more missiles and railguns than a Touhou boss and generally ignoring the laws of physics until he gets murked by, most likely, a Cold War-era fighter with an in-universe market value equivalent to a used Honda Civic.

[u/Temporary_Curve4035 → u/vp917]

Always found it kinda funny in how Monarch could’ve taken the whole exchange. Like Crimson one has ALL the skin in the game and basically tore his itchy nose to spite his face well Monarch is basically a third party getting paid to fight for another country. He must’ve hit the nastiest side eye or found the whole idea hilarious at the prospect of the man who practically had it all falling so hard he’d nuke his own people to get at him.

[u/Le_Golden_Pleb → u/Fayde_Away]

I love Pixy because honestly, who wouldn't go a bit insane after Hoffnung. Also it makes the moral alignment of your character matter more, as you have very different reasons to fight him at the end.

I'm kinda sad we didn't get an actual "hero defects" plot in AC7 for the same reason, but hey, I guess it was ok to go "Belka bad" for a reboot

[u/Ultima-Manji → u/Le_Golden_Pleb]

I feel if someone's really into turncoats and unclear allegiances while piloting some high tech crafts, then Armored Core is a good series to try as well - which I accidentally google half the time because AC gets me both series in the results.

There it's almost expected that half the guys on your side will be enemies sooner or later, with some actually letting you choose routes. And especially Armored Core For Answer is great with this, because the badass opponent on the cover the game hypes up is implied to be the previous game's protagonist. It swaps out the planes for mechs that you have to assemble yourself, but the drama, quotes that go extremely hard, and high-speed maneuvering are still very much present.

[u/Zangakkar → u/Fayde_Away]

Im gonna have to be pedantic but it wasnt until very recently that the idea of soldiers disobeying unjust orders was put into practice. Any time before the mid late 20th century if you were in the military it was very much expected of you to do what you were told when you were told.