Board Thread:Manga/@comment-5774380-20170407184255/@comment-7397205-20170408182446

CaptFredricks wrote: I don't think Ymir has been eaten yet. Jaws resembles her Titan form, but only slightly.

He also seems to have had as much training as the others (Pieck, Zeke, and Reiner) which would not be the case if he was Ymir's successor. True...though right now, I think Ymir would have to be extremely lucky to be alive.

The only way I can imagine her alive now would be if Marley still hasn't found a successor for her, but I'm still convinced that her letter to Historia, which basically told us everything we needed to know about her, was an indication that she's gone.