Is the hidden character unlock have something to do with mc’s memory that was locked in ...

Wait what ... Hidden memory?

So you see, after they defeat the first key master together, they earned an orb. And that very orb make MC recalling a memory that he wasn’t know of, and that very memory got seal into the orb by ML because when he dreamed about it, he wasn’t in a good condition which lead to ML decided on sealing his memory up.

Whoa ... Thank you (づ￣ ³￣)づ