Well, as we all know Shanks has a scar on his left eye which is given to him by Marshall D. Teach aka Blackbeard, the scar was absent on Shanks when he was part of Roger crew
When Shanks visited Luffy at Foosha Village he had scar.
So it is between that period from Roger’s execution & visiting Foosha Village, he received the scar from Teach.
Here’s my theory.
I am going to start with devil fruit which Shanks had (gomu gomu no mi) & devil fruit which Teach wanted (yami yami no mi)
Above you can see , both the df’s have similarities (at least i think that ). Both seems to look similar due to that colour and design. So it is safe to assume that one can get confused on recognising the either devil fruit. And if you are as desperate as Teach well you will.
So my theory is based on that similarities of df.
Now ,when Shanks entered WB’s ship moby dick, the reaction from various crew members were like they were meeting Shanks as Yonko for 1st time, those who fainted on his arrival.
Even Shanks’ conversation with Marco “so ,you are 1st division commander Phoenix Marco” states that Shanks and WB never clashed as “Yonkos”.
So how & when did Teach gave the scar to Shanks ??
I think that Shanks(before being a Yonko) had found a devil fruit Gomu Gomu no Mi from a certain pirate crew somewhere in grandline(mostly new world).
And Teach was already after Gomu Gomu no Mi mistaking it for Yami Yami no Mi, which he has seen in Df book. So when Teach arrived, he found that fruit was already stolen by Shanks. So he planned to get the Df from Shanks & we know how evil planner Teach is .
He joined the crew of Shanks(remember teach wasn’t a infamous pirate then, he always leaved in shadow of WB). He managed to infiltrate the Red Haired Pirates & waited for his opportunity, as soon he got his hands on the Df, was caught by Shanks & at the same time he realised that df wasn’t Yami Yami no Mi.
Now in order to flee he tried to fool Shanks in a meaningless talk, while attacked Shanks when his guard was down giving him a bloody scar on eye with his claw & managed to flee from there.
The reason Shanks scar still ached ,was he was done by the misleading personalities of Marshall D. Teach.
Thanks for reading ^^
4 blades on the claw and 3 marks on the scar of shanks…
Maybe BB had the mythical zoan DF – cerberus that time and he injured shanks with it? That would be cool xD
I mean there were a lot of theories about it and his jolly roger have 3 skulls which resembles a cerberus.
I read this theory and i kinda like it but my point was that the scar wasn’t made with BB’s claw “as a human”.
I hope that the cerberus theory is wrong so that Oda can wow us with something else.
Could be but your theory has flaws… Ootsuki already spotted and mentioned perfectly one of them… also it was said that Teach has been reading about DFs in a book for much time so i don’t think he would make such a mistake… and from when did he became Wolverine?
Despite of all these, it is plausible that he infiltrated the Red Hair Pirates once because he was after Gomu Gomu no Mi or something, that would explain why Shanks was so much “hurt” by him and not physically but more mentally, if it has happened through a betrayal.
It’s funny when you say “attacked Shanks when his guard was down giving him a bloody scar on eye with his claw & managed to flee from there.” and you even put the picture of shanks saying that the scars give him aches. Please re-read that chapter – OP 434 at the very next page, shanks said he was not careless or anything when he got that scar from BB. Meaning BB got the skill to inflict that scar to shanks at that time.