
Unpopular opinion: Emma is the real reason Krakoa fell.
Emma was the one who revealed the truth about Moira to Mystique and Destiny. She did it because she was furious that Charles and Magneto hadn't told her the truth about Moira from the beginning —a pretty weak excuse for wanting to kill Moira— and because she considered Moira's reset powers a threat to Krakoa's existence.
But here's the ridiculous part: after giving Mystique and Destiny that information, Emma refuses to help them with their plan to depower Moira and subsequently kill her. Her excuse was that she “doesn't take sides.”
Seriously? Giving crucial information to Mystique and Destiny, knowing full well that they would want to kill Moira, isn't taking a side?
And the consequences were enormous.
Moira feels betrayed by Krakoa, and subsequently develops terminal cancer because of Krakoa. From that point on, she dedicates herself to destroying the mutant nation.
Which she eventually succeeds in doing.
All of this because Emma was too proud to ally herself with Charles and Magneto, but too cowardly to fully ally herself with Mystique and Destiny.
She literally threw the stone and hid her hand.
IMO, she's one of the biggest culprits behind the fall of Krakoa. She might even be the biggest culprit.