What if "The One You Should Not Have Killed", was never meant to be directly, but indirectly?
For example, killing directly could be any of the MCI, or other children, probably could also mean Charlie as that one.
But if is indirectly, then could mean Evan/Dave, as was killed by an accident, a prank taken too far, and William could have killed him indirectly for being such an ignorant father for not really taking care of his children, causing the death indirectly.
What if "The One You Should Not Have Killed" wasn't someone William killed directly, but someone he caused to die indirectly?
Direct kills = MCI victims or Charlie.
Indirect kill = Evan (Crying Child), who died due to a prank, poor parenting, and neglect.
🔄 "The One You Should Not Have Killed"—Not Literal, But Moral?
The phrase isn't about someone William physically murdered...
...but someone whose death he caused through neglect, emotional abuse, or indirect actions.
Evan (Crying Child), who died in the Bite of '83 due to a prank gone too far, fits perfectly here—especially because:
It was Fredbear that bit him—a machine William created or maintained.
The prank was pulled by his older son, Michael, possibly out of sibling cruelty or misunderstanding.
But William's neglect and obsession with his own work enabled all of this—he emotionally abandoned both sons.
The phrase can mean both ways, as direct murder William Afton did; and as indirect murder William Afton caused.
If the phrase is taken directly, could mean Charlie Emily.
If the phrase is taken indirectly, means CC/Evan/Dave Afton.
In the minigame "Give Gifts, Give Life", there are 4 children, the four missing children from the MCI. There is never a fifth, Golden Freddy/Fredbear.
From the four, Cassidy is born. That pain, suffering, anger... All into C.A.S.S.I.D.Y.
The phrase could have always meant to be for Charlie Emily, as is who brings them back to life, and is the one who starts the revenge.
The children, unable to strike directly, are the providers for Charlie to create Cassidy. Charlie is the one capable of manipulating remnant by herself as Puppet, she could have manipulated the remnant and agony from the MCI to bring Cassidy into existence.