Cyn dies in vacuum trying to prevent Naomi's escape, holding to his belief that she is still one of his people until the end.
Cyn remains Naomi's uneasy guardian aboard the Pella, angry at Avasarala and committed to Marco's dream of feeding and building a Belt free of Inner-planet control. He also insists that great history is made by actual people and asks Naomi not to take a coward's way out, urging her to join the Free Navy for Filip's sake.
When Naomi rushes the airlock at the transition to free fall, Cyn forces his way inside to prevent what he believes is suicide. He calls her family and refuses to leave her, even as she tells him he is not saving her. Naomi opens the outer door; Cyn is blown into vacuum and lost as she makes the jump to the Chetzemoka. His loyalty has become the death she will carry with her.
A huge heavily muscled Belter with close-cut steel-gray hair, pale eyes, scars behind one ear, and a split-circle neck tattoo; his remembered canonical look is warm and protective beneath the hardening of rage.
Cyn was Marco's veteran operative and Naomi's old friend, whose imperfect love for her never overcame his allegiance to the cause.