Jaeha is, fundamentally, a yandere template. They're high charisma when they want to be, have very strong people-pleasing tendencies, and tend to cultivate extensive social networks. They're almost universally some form of gay, but more precisely they need to be a huge disappointment to the person who raised them for reasons that are to a large extent out of their control. They care really deeply about how others see them, and usually have an unmet need to love and be loved. If the yandere adjective didn't make this clear, they're extremely monogamous, obsessively so, and constantly anxious and insecure.

They will almost always be filthy rich and heirs to some kind of dinasty (the og version is the heir to the Samsung chaebol), and will typically have psychic powers of some kind. They refuse to be alted anywhere they don't get the chance to be in a romance. Their obsession and desire to customise themselves to their partner's specs pairs frighteningly well with Bells.

Their original instance is based on the character of the same name from a porn BL manhwa called Guiding Hazard, but they're heavily modified from the original.

Good threads/continuities to be introduced to the character are Guide, Lucid Dream (which I recommend only reading after reading Guide), and Silver Garden.