There are times where Simon isn't Simon.
Most days, when Grace wakes up in the morning, it's to see Simon lying across from him in the bed, blearily blinking open those rich brown eyes as they both try to shake off their sleepiness. They get out of bed, shuffle into the kitchen, and enjoy a nice, quiet breakfast together before they go about their days. At night, they sit close together on the couch as Grace introduces Simon to some new movie or game. Sometimes they just talk. The talking has been happening more as Simon grows more comfortable living with Grace on Erid. Sometimes they cuddle. Sometimes they do more.
It's all cozy and domestic, and Grace loves it. Loves Simon.
But some mornings Grace opens his eyes and looks across the bed at Simon, and knows that it's not Simon looking back at him.
Most often when it happens, he wakes to find Simon's eyes turned milky white, his gaze locked unblinkingly on Grace's face. The teeth that grow out of his left cheek protrude more than usual, and Grace can see Simon's veins have turned black beneath his scarred skin. Simon will reach out with clawed fingertips to gently caress Grace's face, and he'll start to croon. Grace can hear several voices layered behind Simon's, as if many people were speaking through him at once.
"Join us," Not-Simon whispers, dragging his fingertips along Grace's cheek just hard enough to draw blood. "Be one with us."
Grace has learned not to reply. Instead, he calmly gets out of bed and leads Not-Simon to the edge of the artificial ocean, where he leaves Simon with his bare toes sinking into the sand. The moment the water touches Simon's skin, he shifts, changes. Within seconds, he slips into the water and vanishes beneath the waves.
On those days, Grace cancels his classes, locks everyone out of the biodome, and seals himself back inside his house. He puts on music, and stares out over the water that turns deep red, the liquid sloshing thickly across the pebbled beach. If the voices grow too loud, he puts on his headphones, and turns his back on the ocean to drown them out.
He's gotten very good at ignoring the screams.
Very rarely, there are days where Grace wakes up to find Simon already sitting up in bed. Simon stares out at nothing, his eyes blood red and blank, blood leaking down his cheeks like tears. On these days, Grace doesn't touch Simon, doesn't speak to him or acknowledge him. He doesn't need to. Somehow he just knows that wherever he goes, whatever he does, the thing that's looking out through Simon's eyes will see it.
On those days, Grace sleeps out on the beach. He's found that if he stays too close to Simon when he's like this, his skin will burn and his eyes will start to bleed as well.
By morning, Simon is always back to normal.
They don't speak about it. Grace doesn't know if Simon is awake when he's not in control, whether he knows exactly what's happening. He hopes not.
Simon will go days between episodes, sometimes weeks. But sooner or later, one of the things living in Simon's head will re-emerge again, taking over his body once more. And Grace will calmly deal with the visitor as best he can, waiting patiently until the moment the man he loves returns to him.
Grace wouldn't trade Simon for the world. Simon makes him happy, makes him feel loved. So if the price of having Simon around is sometimes dealing with the things the Blood Ocean left behind? Well.
Grace has learned to deal with worse.