#this Ooo is outright hostile to humans i guess

[sicklyseraphnsuch]

Yeah She's Dead

So, little Marcy died in the Winter King's world.

I draw this conclusion based of two facts:

Even post break up, Marcy would not let Ice King mess with Bubblegum for 100 years straight without stopping that mess

There's no Finn around to either help Winter King (because he was born post madness transfer and things WK is the good guy) or help Bubblegum (because timelines are wacky and who's to say Finn wasn't around at the time of the madness transfer)

But there's no hint of Finn anywhere - Winter King made himself helpers to protect himself because heroes don't exist in this world. That's a big clue.

So the lack of anyone helping Bubblegum and also curbing Ice King points to Marcy's death not only due to the lack of Marcy's influence but because:

If Marcy died as a child, the vampires would have feasted on the humans. There's no more humans in this version of Ooo. Ergo, Finn was never born.