The TVTropes Trope Finder is where you can come to ask questions like "Do we have this one?" and "What's the trope about...?" Trying to rediscover a long lost show or other medium but need a little help? Head to Media Finder and try your luck there. Want to propose a new trope? You should be over at You Know, That Thing Where.
Sounds like The Chessmaster.
Could go on Harsher in Hindsight. If the clues to his true nature were there all along then it's not Characterization Marches On — something like Foreshadowing or Rewatch Bonus would fit better. If the scenes are literally shown again after the reveal with the added context that he is actually evil, there is Once More, with Clarity.
Evil All Along? If a previous action was later revealed to have a more insidious meaning behind it, that would probably fit under Cerebus Retcon.
From the Bob example, it appears that he's more underhanded and pragmatic than he seems at first.
Maybe you'd like to check Beneath the Mask or Hidden Depths?
We can never truly eradicate the coronavirus, but we can suppress its threat like influenza
Seconding Cerebus Retcon- Jokes are the most common example, but it can apply in any situation where previously shown/mentioned events are cast in a new, darker light by later installments.
I'm not sure if it belongs to Characterization Marches On, Harsher in Hindsight or Slowly Slipping Into Evil, but I was thinking what trope is this.
It involves a main character in later seasons shown in contrast to his earlier, more heroic appearances. In the later seasons, there is a reveal that shows the main character isn't as morally good as it seems.
Example:
Bob is the main character of a show. He's a Tony Stark plus Bruce Wayne style tech hero that forms a super team made out of interdimensional characters.
After a few seasons, there is a slow, horrible reveal about his true nature. Many of the things he did in earlier seasons are shown in a darker light such as:
What is that trope anyways?