Grasping at straws: Ymir ain’t dead
hmm… tinfoil hat theory here: but we’ve seen with Eren & Historia that people can access memories not belonging to them.
Could it be that Gallard tried that trick with attempting to see his brother’s memories, as Rod used showed Historia Grishas, but couldn’t, but did see Ymir’s?
Supporting evidence 1: Gallard never says he ate Ymir, and when we see him standing in front of her he’s in similar clothes to what he is wearing in the present. No signs of syringes, no rolled up sleeves or third person ready to inject him. Could it be that since he last saw Reiner he went and visited Ymir in whatever location she is being held?
Supporting evidence 2: Ymir’s Titan looks like Gallard’s.
Now that might seems like it should be in the against it column, but consider this: Isayama is a grade A troll (sub note: Bert going to bite his hand at Utgard).
Ymir’s shifter form looks exactly like her regular titan form, something we’ve not seen at any other time (the albeit brief glimpses of Eren and Armin show radical differences). The other noticeable difference with Ymir vs other shifters is that she was a regular titan for 60 odd years, while most are for a few minutes at most.
Conclusion: It’s pretty darn weird that Ymir’s regular form looks so much like Gallard’s shifter form (not to mention the picture book shenanigans). It’s all rather convenient… a little too convenient.
Additionally Gallard says she also wanted to bring back Marcel’s “Jaw” - this could be taken to mean that is the titan designation he now bears, but he doesn’t confirm it. After all he says he was chosen for the operation nine years ago as well - so did he get his titan then?
For instance if he is actually saying (official translation pending):
“This never would have happened if, nine years ago, when I was chosen for the operation on Paradis Island… I had been given the armoured titan instead of you”
Meaning he could be bitter he was given a different titan which meant he stayed back in Marley territory, so wasn’t there to protect his brother.
After all there are NINE titans:
1. King - Uri / Frieda / Grisha / Eren
2. Attack - Owl / Grisha / Eren
3. Colossal - Bert / Armin
4. Female - Annie
5. Armoured - Reiner
6. Jaw - Marcel / Ymir
7. Beast - Zeke
8. Quad - Piku, Piek or however its spelt
If Gallard does have Ymir’s titan, we’re still missing one - who given how the Marley have been talking about their war effort should have been fighting with the others, or at least mentioned - so it could well be that Gallard is actually the as yet unnamed 9th titan and Ymir is just being held captive.
“But why would they just hold her captive not take her power back?” I hear you ask.
Well for one, she’s shown herself to be a (somewhat) willing prisoner, and thus a source of information about the wall society / military. She’s also shown herself as having rather flexible loyalty towards the vast majority of people in the walls.
And secondly, she’s leverage against the only other branch of the royal family outside Zeke and (translation & horrifying implications for the other, especially female, shifters pending) his kid - Historia.
If the Marley forces want to get control of the coordinate (seeming to be unaware of the First King’s trap), they want / need a royal bloodline. So a reasonable plan would be to defeat Eren so they can get their control over the co-ordinate and the titans, then use Ymir as bait to get Historia to come with them, and have more royal blood available and a puppet to take over the island more peacefully.
Thirdly, if Gallard has been a shifter as long as Reiner, the Marley might not have had a suitable candidate to take over Ymir’s titan - Gabi, Falco and co are all still around 10-12 years old, so when Ymir arrived they probably would have only just begun their training.
So if Ymir was a passive prisoner there would not have been the urgency to take the power from her, especially as we’ve seen with Eren how hard it is for someone to learn to control their power.
Additionally with the Marley’s comparatively advanced technology they would find it easier to keep Ymir contained even if she did turn hostile - put her in a concrete vault with only narrow staircases out and she’d have a very hard time escaping.
And lastly, from a narrative point of view, there are very few deaths that have not been shown explicitly - especially of named characters. So while it is possible Isayama hecked this up big time, that we weren’t shown regular titan Gallard standing before a chained up Ymir, but rather casual wear Gallard, feels significant.
But this may well be wishful thinking of course