A mysterious woman who's been Trent's constant companion for a few years now, ever since he left the Brookside Institute. He's the only one who can see and hear her, and the only other person who knows about her existence is his therapist, Corrine. She can move freely through physical barriers, fade in and out of sight, and she can change the appearance of her clothing seemingly at will.

Lydia is incredibly loyal to Trent, always ready to encourage and advise him-- though her advice is sometimes, perhaps, not the wisest to follow through on. Lydia is very neurotic, sarcastic, and bold. Often telling Trent things he doesn't want to hear, but that she thinks he should.

As the series progresses, Lydia struggles more with her origins, unsure as to who or what she is-- whether or not she's some sort of spirit, otherworldly being, or a manifestation of Trent's troubled psyche. She longs to have a life for herself, and to be able to physically experience the world around her. 

She shows occasional jealousy when it comes to other women in Trent's life, though whether that's down to romantic feelings on her part, or simply fear of losing the only human she can seemingly interact with-- who can say? She also does not like Chloe very much.