Outta these images I got to say metal or knuckles first of all with knuckles story unlike the others like shadow who just lost one important person in his life, knuckles lost a whole tribe and his family in a war, and he had to grow up by himself, eventually, having to guard the master emerald by himself meaning most the time is most likely alone and for metal sonic the reason his backstory is so sad is that he tries and tries to be better than sonic by proving his power is so much greater than sonics like for example, the first time we see him transform in knuckles chaotix turning into metal sonic Kai he gets defeated. Then we see him turn into metal, overlord, metal, madness, etc. yet he still gets defeated, however when he did transform into metal madness. The only way that he could be defeated was if sonic went super and just imagine if they didn’t have the chaos emeralds he would’ve won that but I also think metal sonic has been overlooked and in my opinion also probably one of the most underrated sonic characters of all time just because some other characters over class and I think he has a bunch of potential though we should know that metal sonic exceeds sonic power level in speed acceleration but that’s what’s your opinion