Iron Man 3

Stark has panic attacks and builds forty-two suits he doesn't need. A terrorist called the Mandarin bombs targets across America. The reveal: "the Mandarin" is an actor, Trevor Slattery, hired as a front by Aldrich Killian, who runs a regenerative treatment called Extremis that makes subjects explode when it fails.

Stark destroys his armours and has the shrapnel removed. It doesn't last, but the intent — to be a person rather than a weapons platform — is the arc.

The Mandarin plot, properly explained — because it's spread across two films eight years apart and almost nobody gets it first time.

Layer 1 — the con. Killian's Extremis subjects sometimes explode. To hide the failures, he invents a terrorist called the Mandarin and claims the explosions as bombings. He hires Trevor Slattery, a washed-up British actor with a drug habit, to perform the role on video. Slattery has no idea what's actually happening — he thinks he's landed a great gig with good catering.

Layer 2 — the theft. The name "the Mandarin" was never Killian's invention. It was one of many names accumulated over a thousand years by the very real Xu Wenwu, who runs the very real Ten Rings organisation. Killian stole a living man's identity for his cover story.

Layer 3 — the consequence. The real Ten Rings were, understandably, furious. They abduct Slattery and keep him alive as a court jester rather than executing him. He resurfaces in Shang-Chi (film, 2021) living in Wenwu's compound, and again in Wonder Man (series, 2026) as a free man after a decade inside.

So: Iron Man 3's villain is a con man impersonating a man who was alive, powerful, and extremely annoyed about it.