Ultimately, it isn’t Maeglin’s malice that dooms Gondolin, but his fear and greed. When offered the right incentive (power and Idril, the two things he most wants), he readily becomes the traitor Turgon fears and the doom of the Noldor predicts. But Maeglin’s betrayal isn’t as fruitful as he hoped—instead, he falls victim to his own curse, placed on him by Eöl and fulfilled when Tuor throws him from the walls.