This article or section includes speculation, observations or opinions possibly supported by lore or by Blizzard officials. It should not be taken as representing official lore.
This is rumored to be released in future patches, there is NO conformation though.
"Pack Mule — Summons a pack mule, giving you access to any bank items for 3 min. The mule may only be summoned once.
Summon Faithful Mule — Summons your faithful pack mule, giving you access to any bank items for 3 min. "