Sorry, Knuckles, you're not my rival anymore, despite being my polar opposite in every way, design-wise and character-wise.

Sorry, Metal Sonic, you're not my rival anymore, despite being the antithesis of this entire franchise, which is based on nature and freedom.

Sorry, Jet, you're not my rival anymore, despite being the fastest in the air, and I am the fastest on the land, and having similar personalities while literally competing for a similar goal

Sorry, Blaze, you're not my rival anymore, despite being my 1:1 dimensional replacement

Shadow, he just... perfectly matches my strength (wears rings to limit his power) and speed (has rocket-propelled shoes), he completes me...