1. Characters start and journey, inexperienced, almost gets eaten while in Titan form and can’t control it as well. Still gets his ass kicked in by Annie at the first meeting and kidnapped.
2. Survived, didn’t beat her as he technically lost as Annie ran away toward the wall. Anime berserk mode is a inconsistent as it never shows up again, more of a shows flaw than anything. Unless you think Luke is also a Mary Sue because he survived after Vader chopped his hand off.
3. Not sure if you’re talking about WHT or AT so I’ll elaborate both. 1st battle with AT, was about to beat Reiner because of his experiences learned from Annie’s tactics, finally gaining complete control of his Titan only to be defeated by the falling CT body, gets captured. 2nd battle with AT, hardening ability was mastered after many experiments, not something he could do right away. For WHT, Erens already had years worth of experience and planing and from the development from the other arcs, we can see a clear line how we got from point A to B to C with his character. Eren wouldn’t even have won unless his friends didn’t come. A Mary Sue would be able to hand this all on their own without development.
4. Wow the MC survived the last chapter, totally good example of a Mary Sue, right Captian America?
5. He got to be OP because he bettered himself and his character developed, he didn’t start off as the “most op titan”. Clearly he got his shit pushed in a lot and had to learn to use these skills and powers.
Eren would be a Mary Sue if almost everyone liked him, him knowing how to do everything or taking a couple of seconds just to master something and some how winning all the time or coming out perfectly fine without any revelations or character changes and development. But it’s clear Eren isn’t like that as a character. Get fucked bitch.