Aside from making it possible to advance to the next Mount rank, you can use the Tame feature to increase the stats of maxed out Mounts (and in turn, further increase your character’s CP). After taming, the stat boost that will be applied to the mount will be random. Taming can be done by tapping the Tame tab in the selected mount’s page. You’ll need to spend consumables called Soul of Mount Tame, which you can buy from the Guild Shop for 40 GC (Guild Contribution pts) each. This item has a 50-pc weekly limit.