Eliza feels like that one creepy side character who’s in the background of every shot. She’s always there, liking your posts, but in the context of the story, she’s the watcher. Eliza is theory fuel, rather than a tangible character in the narrative; she might be talked about vaguely, or perhaps her presence can only be inferred by background events.
As explained earlier: you are the Best Friend, the deuteragonist who’s more interesting and capable than the actual protagonist, although the story doesn’t entirely revolve around you. Not evil, you aren’t the killer. You probably got into trouble more than a few times growing up because someone else needed help or a distraction.
This measured and reasonable friend of yours is hysterical because they’re being stalked by a ghost, or chased by a killer? You aren’t scared for your own safety, you’re concerned about their wellbeing. If you receive a weird hate email from them, you go over to their house for an explanation and listen when they beg for you to believe they didn’t send it.
If you die, it’s shown on-screen and it’s probably really sad to drive in the feeling of despair that you actively work against. You’re simply too effective for the author to write around. If they don’t do that, you eventually become the protagonist, the Ellen Ripley, spawning an action franchise and you become an icon forever.
Unfortunately, I specifically don’t know you very well. That probably means you aren’t a main villain, but you aren’t a member of the main group. Perhaps you appear in one episode which revolves around you, and then appear a few seasons later, before disappearing forever without explanation. If I could have more data, that would help a lot.