And very casually also we have this by Oda about Zoro being Number Two/Right Hand Man/First Mate and being close in strength with his captain and always fighting his right hand men and number twos counterparts in other crews.
You all know that the strongest Strawhat bar Luffy is Zoro. And if by chance you didn't know... Oda just stated this. No equals, no peers, no Wings, no shit... just an undesputable number two which is Zoro, with no one close enough to make this ambiguous.
No King + Queen, Rayleigh + Gaban, Zoro + Sanji. Oda has only King, only Rayleigh, only Zoro.
Zoro who, coincidentally, is also Luffy's Right Hand Man and the only Strawhat whose strength compares to Luffy's, who has similar traits, powers and goals to Luffy; they as a duo of Captain/Number Twos are consistently paralleled with other duos of Captains/Number Twos, and Zoro alone by himself is paralleled to these guys by themselves.
The amount of material proving this is gargantuan.
Can one our special friends explain all of this?
Don't be shy... entertain us with your mirror climbing skills!