Do Halbu and Jamella have any lore?

Halbu and Jamella, the vendors in the Pandemonium Fortress, are quite mysterious characters, with very few spoken lines and just two purposes: repairing/vendoring and giving quests.

On their wiki pages there aren't any useful informations about them, so I was just wondering: has there ever been any Word of God about their lore? Are they just there to be useful? This always seemed odd to me, especially considering the deep lore that's always been a distinguishing trait of Blizzard's games...

Halbu and Jamella appear to be a warriors chosen by Heaven to fight Hell, as Tyrael mentions that many mortals have journeyed to the Pandemonium Fortress. Perhaps their near silence is a result of their prolonged and never-ending battle against the Burning Hells.

Thats what I've gathered from my Diablo 2 strategy guide from ages ago and relistening to Tyreal talk :P, plus the wiki i found says the exact same thing. :)