Most people who are daring enough to endeavor and compete have at least one rival who pushed them, tested them, matched them tooth and nail, and perhaps got the better of them on more occasions than one cares to admit. They're the ones who made you better because they were always opposite you, forcing you into that uncomfortable place where you have no choice but to hone your skills; get better, or quit. Let's imagine Thanos is old and gray, sitting on a porch in a rocking chair, iced ambrosia in one hand, a neutron star smoking pipe in the other, waxing philosophical on days long gone. Who would Thanos say was his one true rival? Not an abstract entity or group, but one individual. Does one exist? If not, should there be?