Did Eridan go grimdark when he killed Feferi, Kanaya, and almost Sollux?

Yes, and no. I was told Hussie did describe Eridan as going ‘grimdark’, but if that’s true there’s an interesting thing to look at regarding the difference between grimdark and Grimdark. Thematically, and even visually during the scene, Eridan went grimdark- As in, suddenly there was a gritty and dark turn of events and everything went to hell and he was being creepy and killing things. But he didn’t go Grimdark, as in the state of corruption Rose undergoes. His skin didn’t ACTUALLY get a darker shade of grey, nor did he get a power up to his abilities, that was just him exerting the power he had to fuck people up.

On the contrary, both Rose and Jade were corrupted by external influences, and had their personalities altered. Rose became more single-minded on revenge, Jade let all the bad stuff inside her flourish. On top of that, I would even dare to say JADE isn’t Grimdark- If we consider Grimdarkness as the state you undergo when the Horrorterrs Corrupt you, she is, in fact, Grimbark, as she helpfully tells us. Her personality is corrupted, but by Condy, and… It’s arguable if she actually gets a power boost or not. Rather, it seems like she simply… Doesn’t have any issues bringing out her full power.