>>116615901Technically SGRUB is what went wrong in the moment but it's always doomed to fail. Eridan's purpose in his pale ship with Feferi was to prevent her overbearing lusus from killing the rest of the planet by killing other troll's parents and dropping them into the ocean for Glyb to feed. In an extant sort of way his purpose was to make sure she survived as the Heiress, which is demonstrated with his idle chiding to getting her more aggressive or at least act like a proper seadweller.
You have to remember that once Feferi comes of age she'd have to face Her Imperious Condescension in a one-on-one battle for right to rule. In countless sweeps not ONE Heiress ever won against her. Eridan had to know that Feferi was doomed as fuck and still put his all into making sure she wasn't unhappy.
Feferi meanwhile was an idealist and never could see the words on the Alternian wall that her brutal society she existed in could support her new ideals. This is even furthered by her lack of any kind of visible power to enact her will as an Heiress upon the planet compared to Trizza. Feferi sees Eridan (one of the most typical Alternian trolls of the 12, next to Vriska) as something that needs changing because he does not fit what she feels is right for society. She is not nearly as successful at changing him, aside her happiness being contingent on him not going on a land-dwelling genocide run.
This does make their moirailship 'work' but only as long as both their perimeters are maintained. This is also why once SGRUB starts and Feferi's duties no longer exist that terminating the relationship comes up; she no longer has the necessity for it. Eridan goes from a world he perfectly fit into to being practically useless, unwanted, and unimportant in almost every metric. Not that it would have been a happy ending if SGRUB never happened, Feferi never would be capable of defeating HIC so she's just doomed to die no matter what Eridan does.
