Affinity
An affinity is a bonus to skillgain in a given skill or characteristic.
Each character is created with one random affinity. The player developes a new affinity after one month real time if he has not uncovered or received an affinity yet.
Additional affinities may be gained by killing other players in combat, provided the opponent is premium, has an affinity, and is of an enemy kingdom. It is possible to gain up to five affinities in each skill this way.
Skills for which you have an affinity can be seen by an asterisk symbol (*) next to their name in the skills window. Note that if you have not unlocked that particular skill yet, by using it, it will not show up even if you have an affinity for it.
The effect on experience gain is 10% per affinity, stacking up to 5 times. It would be reasonable to assume that the maximum possible skillgain accrued from affinities (at the maximum stack) would be in the range of 50%.
An affinity in main Fighting skill does not seem to have any effect, except when skilling up to 20 with a practice doll.