While many of them are terrifying, I personally choose the Overlord as I actually used to be scared to the final episode of season 2 because of him, I guess that's what him scary to me when I was a child, In most other shows I would watch as a child, I'd never seen the characters I love, so hopeless before.

Also on a side note Hexsmasher you seem to be a Ninjago fan, I've actually been a long time fan of the show since 2011.

Guilty 😁

Koh because he’s so beyond human it’s terrifying, also the way he and the scene was played was very tense so there’s that as well.