I can see Human characters getting "privilege", social" or "convenience" bonuses when interacting with the rest of the gameworld.
Example: Clothing and equipment is designed for humans. Any other race has to get their stuff specially made (which will cost more money).
Example: Some generic Magickal stuff is more likely to work for humans (or work more effectively). Potions, for instance, are designed for the human magic-alchemical-biochemistry. There may be some nasty side-effects if potions are used by other species.
Example: Racism. Perhaps something like "Non-humans have to leave the City before dark". Or "Non-humans have to pay special taxes". Or "only humans can possess weapons (or use magic) in the City".
Of course you could also use something really simple. Maybe humans are just favoured by the gods and get plus 1 on all saving throws or an extra spell per level
Example: Clothing and equipment is designed for humans. Any other race has to get their stuff specially made (which will cost more money).
Example: Some generic Magickal stuff is more likely to work for humans (or work more effectively). Potions, for instance, are designed for the human magic-alchemical-biochemistry. There may be some nasty side-effects if potions are used by other species.
Example: Racism. Perhaps something like "Non-humans have to leave the City before dark". Or "Non-humans have to pay special taxes". Or "only humans can possess weapons (or use magic) in the City".
Of course you could also use something really simple. Maybe humans are just favoured by the gods and get plus 1 on all saving throws or an extra spell per level