You are an authorized agent of the Mojave Express Package until the delivery is complete and payment has been processed, contractually obligated to complete this transaction and materially responsible for any malfeasance or loss.
Daniel Wyand is the fourth Mojave Express courier in 2281, a fellow co-worker who didn't survive a bullet to the brain. His corpse can be found in the town of Primm lying outside the Mojave Express building.
Besides the Courier, he is the only other in-game character who is carrying a Mojave Express delivery order. Daniel's package consisted of two over-sized fuzzy dice, which has been delivered to New Vegas according to Nathan.