Hermes: Hermes and Kino have a special bond that goes beyond that of a simple friend. As between all motorrads and their riders, they have a mutual contract—Kino provides the balance, Hermes provides the speed, and together they can go anywhere they wish. In the new 2017 anime Hermes says that motorrads are happiest when they are running because that is what they are supposed to do so he is grateful to Kino because together she helps him run.
Kino (original): Kino was a traveler that visited The Land of Adults two days prior to Sakura's operation date to turn children into adults. During his short stay he was able to make an impression on young Sakura that opened up her mind and spirit to travelling. On his last day, Sakura asked whether or not she could skip the operation, consequently infuriating her parents. Kino took the knife that was meant for Sakura and was mortally wounded as a result. Sakura changed her name to Kino shortly after escaping from the Land of Adults and became a traveler as a constant reminder of why she is still alive. The original Kino passed on his desire to travel, some of his philosophy, and unintentionally provided the new Kino with her constant companion Hermes.
Shishou - After Young Kino/Sakura escaped from the Land of Adults, Hermes ran out of fuel and she was left to starve or die of thirst. However, as luck would have it, Master found Young Kino/Sakura and nursed her back to health. Young Kino would then become Master's pupil in the mastery of survival, gun skills, and travelling for three years. Master was the original owner of the 1851 Colt Navy Revolver Kino is known to travel with on her right hip. Although it is implied that Kino "inherited" Master's revolver, the sidearm was actually stolen alongside food, medicine, fuel, (and metaphorically, Master's luck), when Kino initiated her journey as a traveler. Kino is requested many times who her mentor is, however Kino simply tells them, she taught herself in order to protect Master's identity for her own safety.
Shizu- In "Colosseum -Avengers-", (both in the anime and light novels), Kino meets a master swordsman, named Shizu, who was the prince of the Land of Tournaments. During the finals of the tournament, Kino fires a well-aimed explosive round that kills the King, which was Shizu's objective all along. They go their separate ways although their similar travels allow them to intersect paths occasionally. Shizu travels with a big, fluffy, white talking dog named Riku and later with a small girl with a fondness for explosives.