So Zoro will have a bitter end
See Ark Fishman...In the manga we cannot see Luffy face...But in the anime, one of Luffy's eyes is hidden..I still believe that teach hurts Luffy like Shanks face
I believe Blackbeard gonna lose his Right Eye, if he puts an Eye-Patch on it or not, i'm not really sure.
However i wanna explain something, Eye-Patches in real life are not just for losing an eye or hiding a scar
They were actually used due to how dark the captain's cabin can get inside the ship at night, so usually some Pirate Captains would keep one eye shut (Using an Eye-Patch), to get used to the dark, so most day they are using their non-covered Eye, but during the night when they get inside the ship, they switch to the other eye
It's obvious that Oda researched this & it's what he is aiming for with this Character, that's why he made him the only one with an Eye-Patch even though this is a Pirates Story of +1000 Chapters. So the symbolism is that this Character is waiting for a certain event to finally reveal himself, someone who is prepared for the darkness. And who represents darkness? It's obviously Blackbeard
This is why i believe this person is either Blackbeard or an Old Legend waiting for the final events & fall of final villains, similar to how Kuma arrived in Thriller Bark near the end & was waiting until Moria was defeated to finally introduced himself
The reason i mentioned Zoro isn't because i'm just fanboying or anything, it's based on a simple fact
All SHs will do a Feat at the end of Story that no one person can mimic, a Unique Feat where they remove an obstacle that other people are unable to
For example Usopp defeated Perona in Thriller Bark, which is a Feat that no other Straw Hat could have done & Oda made sure to show us that or Chopper was able to temporarily influence Cindry even though she was a Controlled Zombie ... etc
So EOS after Zoro becomes Greatest Swordsman & forges Strongest Sword(s), Oda must introduce an obstacle that only Zoro's Swordsmanship can solve, but if it's an obstacle that needs to be destroyed, what does stop Franky from using Pluton on it for example? Cuz as i said, it must be something that only Zoro can take care of, nothing else can, so it can't be an Object
The only explanation is that it must be a Character who cannot be damaged, someone even worse than Kaidou, which conveniently Kuma also represented in Thriller Bark Arc, he was indeed enhanced that even Sanji's Kicks & Canons are useless against him, Zoro was literally the only character present at the time who was able to injure Kuma, and afterwards Kuma was impressed by Zoro & decided to leave them alone in exchange for showing Zoro Hell
So once this Character appears who is awaiting for Final Arc events, possibly someone who wants Luffy because of the Dawn he just triggered, he will appear Post-Final War, what does he truly want? Most probably the throne, because with Yonko & Im-Sama & Celestial Dragons gone, this Character believes he is the one who should rule the world, because he is strongest & humans are not worthy to rule.
This is where Zoro's Final Moment comes in, to show not only this character but also the entire world that Humans are indeed powerful, Zoro will injured this Character using his EOS Swordsmanship, Haki & Final Swords (I believe Zoro's Sword is gonna surpass Black Blades), so this Final Character will be impressed by Zoro's Development & how he views Humans will change. Whether Zoro actually defeats him, or he just decides to step aside similar to Kuma in Thriller Bark, is for Oda to decide
But i'm very confident that this Character is a Giant from Sun God Nika Era & he is Strongest of all times, he have an Eye-Patch & most probably a Largue Redbeard