was it ever mentioned how elias feeds the eye? he doesn't seem to read statements so what exactly is keeping him alive?

same for martin-- shouldn't his adjacency to the lonely make him need to feed it?

is jon the only one who we actively see and know about how he feeds his entity?

The Eye is the fear of being watched, having your darkest secrets known, that people will stand aside and not help you when you’re suffering, and probably some other things. I don’t think every Avatar of The Eye relies on, or even have anything to do with, Statements.

It was always my assumption that Elias is the one watching Jon in the first season, though it may have been The Eye itself.

Either way, I do think he will hire people like Martin, that aren’t necessarily qualified for their jobs and are scared of being found out. Found out specifically by him, their boss.

He also can, canonically, see through the eyes of things that depict eyes, most likely giving people the unnerving feeling of being watched.

(EDIT: I completely forgot, he can also literally read minds, so he likely will do what he did to Rosie, and say things that allude to what they’re thinking, unnerving them and making them self conscious.

He also blackmails people, so there’s that.

I think Elias is fed by a lot of smaller, more passive, fear, there’s just so much he doesn’t need to be concerned about The Eye feeding on him.)(I also think his form of Eye fear is more “knowing your secrets” than “watching your suffering”)

As for Martin, I’d imagine that his own loneliness was feeding the Lonely, Melanie is antagonistic towards him, Basira is likely indifferent about him, Tim, who you could probably call his friend, just died, Jon was in a coma, Sasha is dead. He then decides to isolate himself from everyone, so it’s probably that.

Personally, I think he was also feeding on Jon, once he woke up. During season four, he avoids any interaction with Jon, when they do interact he is dismissive or outright condescending to him, and he sets the few people Jon does have around him, Daisy, Basira, and Melanie, even more against him than they already were.