William "Mac" McCarthy

William "Mac" McCarthy and his two brothers (Robert and Steven) are the proprietors of McCarthy’s, which according to Mac is his successful general store back east. Mac and his eldest brother Robert went to Can-Town to establish a second McCarthy’s along with a regular caravan to link the two, and it seems that most of his caps have been tied up in that investment. To fund his ventures and stock his shelves, Mac scavenges vaults and old buildings.

Mac appears to be in his mid to late twenties. He is less than five and a half feet tall and around 130 lbs.

Mac acquired the modfied Pip-Boy of Dr. McKinsey (a.k.a. the Wiley Wasp) and further modified it by incorporating the compatible components of an Power Fist brand Shocker and dubbed it the "Pip-Guy". Mac drew up plans for further modifications of the Pip-Guy which would incorporate pieces of power armor. However, he was informed by Walker's mechanic, John Paul, that the additional modifications would require upgrading the Pip-Boy computer system so that can automatically balance itself to match Mac's movements without injuring him. Prior to leaving for Vault 99, Walker completed the modifications of the Pip-Guy Mk II.