When season 8 starts and the new Hermit is introduced, Grian sees Pearl and turns away. He goes north, messes around with Mumbo and Scar, forms Boatem with them and Impulse.
His sister follows him, talks to him, but he ignores her. He looks away, doesn't answer, acts like she isn't real.
Ever since the Watchers destroyed Evo, Grian has been haunted. He's never been sure if they're actual ghosts or just hallucinations caused by his guilt, but the Evolutionists are there. Not all at once, not all the time, but there isn't a week that goes by that one doesn't appear for at least a few minutes. Sometimes they yell, screaming condemnations for letting them die or accusations of betrayal. Sometimes they cry, mourning their deaths and the end of fond memories. Sometimes they do nothing at all, standing there, staring at him.
He used to talk to them, begging forgiveness, trying to hold onto what was left of his friends, but the longer the conversation the harsher their words. It always ended the same, with ghosts screaming rage and Grian curled up in a ball, crying, unable to escape.
You couldn't run from a ghost.
Grian couldn't take the screams, couldn't face the constant reminder of his failure, so he turned away. He ignored the ghosts, pretended he couldn't hear them. Surprisingly, he found that it actually worked; if he focuses on something else, distracts himself well enough to forget they were there, he'd later realize they were gone.
Or, most of the time they were.
Pearl has appeared plenty of times before, and it always hurts, even more than Taurtis. She'd joined Evo after the Watchers showed themselves, after they all realized something was very wrong. With the others, Grian at least can justify that none of them had known, but with Pearl he doesn't even have that paper-thin excuse. He was supposed to protect them, but all he did was lead them to their deaths.
But now something is wrong. Even at their worst, none of the ghosts ever stay for more than an hour or two. But Pearl is staying, following him. He ignores her, focusing on his starter house, but she doesn't so much as flicker.
Days pass and she's still there. He does everything he can to distract himself, even going so far as to fight the ender dragon, but she's still there. It's the longest, most consistent haunting he's had. He tries so hard to ignore her that he ends up ignoring the Hermits. He forgets to eat and dies of hunger. He's constantly spawning phantoms; he hasn't slept since the season began.
But no matter what he does, Pearl is still there. Haunting him.
He doesn't know how much more of this he can take.
Meanwhile, the Hermits are very confused and worried at Grian's very out of character behavior, and Pearl is both incredibly surprised to see her dead brother alive and increasingly frustrated that he seemingly can't see or hear her.