saw a knuckles fan describe shadow analysis as "just describing knuckles" because "shadow isn't nice" and "he isn't secretly a softie" and. this is kind of what i mean when people act like character traits can only belong to one character
shadow IS actually a softie and hides this part of his personality from others very frequently. he hid his tears from rouge during shadow generations, he adopted a chao (with a unique design so we know it's the same chao) that you can find in a lot of his official art (and if you consider idw canon, they gave that chao a backstory and show him adopting the lil guy almost immediately), he went out of his way to keep rouge safe during the sonic racing crossworlds official animation.
he went out of his way to buy an expensive and sweet gift for amy in tmosth (and he bought a second ticket so she could bring one of her friends!), he went out of his way to protect sonic in forces against his own doppelganger even though sonic could've Definitely handled the clone on his own, he gets concerned when people he cares about are targeted.
he got distracted by a beautiful sight in a sonic channel story, carefully carried maria around the ark when she overexerted herself. he's a poetic guy and actually IS very soft, he just makes an effort to not show it because his big heart has almost destroyed the world in the past.
like im sorry, knuckles and shadow are just actually similar. it really does come down to if you want the guy whose open about all those traits and has 0 backstory or the guy who makes concerted effort to hide all those traits and The Most Backstory Of Any Sonic Character.
if anything one of the biggest differences between the two is that knuckles it probably less polite than shadow and less formal, while shadow is Extremely formal and polite (at least they make an effort to differentiate the speech styles between the two in japanese AND english)
like they're both protective of people they care about, get annoyed easily by sonic (shadow is a little better at monitoring his reactions around people who aren't sonic, iirc), can be quick to take action without all the details (shadow is SLIGHTLY more likely to wait for all the details unless im completely misremembering, knuckles has been tricked by eggman 3 separate times), very powerful (shadow shows this in being skilled with chaos energy overall while knuckles primarily shows this in physical strength and being able to use the master emerald), able to rival sonic (shadow with his speed and chaos powers, knuckles with his physical strength), etc.
the biggest differences between the two might literally be the fact that shadow has a backstory and knuckles doesn't. i literally have trouble thinking of differences between them (and i'm SURE more exist) aside from their relationships with other characters or their individual powers. maybe the fact that knuckles is significantly less likely to hide his emotions than shadow is?
but people WILL just invent additional differences between the two characters because they personally believe knuckles is the only tough guy with a soft heart in the franchise and are mad people like the other one.
i need knuckles fans to be normal before i start disliking the character as a result of this constant exposure to complete bullshit of "NO MY CHARACTER IS THE ONLY ONE WHO CAN DO X, STOP TAKING HIS THINGS" that i see nonstop.
