“Tempest Blazers are the cavalry of the Militant Order of the Arcane Tempest. From atop their mounts these pistol-attuned sorcerer-soldiers harry enemy formations with arcane firepower. Even at full gallop Tempest Blazers wield their magelock pistols with deadly accuracy and imbue their rune bullets with supernatural lethality to penetrate magical protections and wards.”
The real question though is whether or not you think using them on the battlefield is a good idea.
Let me know if they work their way into your army lists.