Dipper Pines

Biography
Pre-Transcendence:

Before the Transcendence, Dipper was a normal human boy with a love for uncovering secrets. Spending the summer with his twin sister at their Great Uncle Stan's house in Gravity Falls, the two spent the summer solving mysteries and uncovered something far beyond their own ability to understand.

Post-Transcendence:

After the Transcendence, Dipper became the demon Alcor, having absorbed Bill Cipher's remaining energy into him. At first, only Mabel could see him, but as his power grew, more people could view him without a physical form. With his powers over dreams and the Mindscape, he becomes the focus of cults and summons from people all over the world. For now, it's only been 18 years and he glitches in and out of it at times, but most can see him - So long as his attitude is positive or at the very least, angry. Anything like sadness will cause the growing demon to disappear entirely.

He'll return when he feels better.

Personality
In many ways, Dipper retains the personality he had when he was a human boy. For a demon, he can be quite caring when it comes to summons regarding children, and he still enjoys spending time with his sister Mabel and her family. However, Dipper can often display a more menacing and morbid side of his personality at times since becoming a demon, and if pushed too far, can even lose himself to these feelings for a time. His personality changes greatly over the course of his immortality, going through periods of more cruel and typical demonic reigns that are always connected with a lack of human interaction. He tends to be the worst in between Mabel's lifetimes, but reconnecting with her - and others - always slowly brings back his more human side. Dipper has no interest in romantic or sexual relationships (aromantic and sex-neutral asexual) - though it's unclear if this was a forced change outside of his control due to his transformation, if he was that way all along, or he subconsciously avoids those relationships willingly due to feeling inadequate for such a thing as a demon now. However, he is perfectly capable of platonic love, and forms many close friendships over the centuries.