Responses
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IKR?? I mean Armin is already a loveable character on his
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Own
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I agree with you on this and to make it more trustworthy, remember the ones who were near the mule titan when it took Zeke away were, levi, hanji and jean...and when piecke fell. In page one of chapter 100. She said she have seen that soldier in paradise. So it might be one of these 3, I believe. It's most likely jean now.
Armin can not be billy, as we all know that billy is a part of the tybur family which is an old family that have a lot of connections with others tribes and nations...
Also, didn't Armin and eren fight to get into MARLEY and stop the ships so how could he have infiltrated marley in those 4 years and made all these connection?
It shows clearly in the manga that billy is popular and loved, and remember what nanbia said when she saw him and they talked about their childhood and how she was sush a crybaby ?
You can not say that "Armin" is " billy" based on appearance only. Not a trustable theory my buds