You graduated from the elite hippogriff-riding school of the Endrin Military Academy. Not only can you ride a hippogriff with great skill, you have also formed a close bond with a particular mount.
A Sable Company Marine has the following class features:
You can gain a hippogriff as a companion. This ability works identically to hunter's bond when used to gain an animal companion, but can only be used to gain a hippogriff companion. You gain a +2 bonus on Ride checks made when riding your hippogriff companion, and whenever you are within 20 feet of your hippogriff, it gains a +2 morale bonus on all saving throws made against fear effects.
Starting Statistics: Size Large; Speed 40 ft., fly 50 ft. (average); AC +2 natural armor; Attack bite 1d6; Ability Scores Str 15, Dex 15, Con 14, Int 2, Wis 12, Cha 9; Special Qualities darkvision 60 ft., low-light vision, scent.