When Grace dies he asks for his body to be turned to ashes, and then into a statue. The statue has him sitting, legs crossed, arms curled slightly, with his palms on his knees. He says in his final message there is a reason for this very specific positioning, but that he can't say what it is.
Time continues forward. Rocky and Adrian grow and change. They move house a couple of times. Rocky changes career from engineer, to inventor, to scientist, to diplomat, to teacher. Adrian picks up a new hobby every few decades. They explore other parts of Erid they've never seen. They meet humans on more than one occasion, but there's something about it... Something not quite right. The Eridian mind can never forget, and no matter how much time passes, Rocky feels it. Missing Grace. His human.
And then time really does move on. Rocky walks stiffly, Adrian sleeps for weeks at a time, they both eat less often due to how draining it is.
And one day, the temperature is perfect. Adrian wakes earlier than they have in years. The warmth loosens Rocky's arthritis, the wind is quiet that day, and sound can carry for miles because of it. The soil is quiet, ready, resonant. And they both know.
They go for a walk, take a dip in the sea, attend a choir in a crystal cave. And then, without fanfare, when no one else is around, they visit Grace. And Rocky climbs into his stone lap. And Adrian curls their body around Grace too. Just like Grace did hundreds of years ago, they let go, no scream, no pain, just peace and togetherness. Too beautifully intertwined to ever untangle.
And there they sit, three stones, for the rest of time.