Most people are a little sceptical about tieflings. Firstly, they're not terribly common, making up a very small percentage of the world's population. Secondly, they look like devils. Because of this, tieflings tend to exclude themselves from society, often seeking to make a name for themselves and then soaring ahead of their peers in order to avoid unpleasant interactions.
The infernal heritage of tieflings is pretty obvious, their horns, tails and abnormal skintones making it hard to hide. Outside of this, they look a lot like humans, though some have stronger signs of their devilish ancestors as well. This can be sharper teeth, claw-like nails or forked tongues. It is also not unusual for tieflings to have eyes in a single solid colour, or normal eyes with a strange colouration.