Pathfinder Society Casefiles
Makes his own Coffee & gunpowder: puts Fiendish Brimstone in both.
A Rakshasa—spawned tiefling, Whisper simply “happened” to be passing through when the slave revolt occured, and just happened to lend a hand.
He also just happens to be the bastard child of demonic nobility, just happens to have some kind of link to Grandmaster Torch’s conspiratorial organization, and just happens to be one of the few gunslingers in the world.
He’s totally just a mercenary. These are all coincidences.