Made at the X-8 research center through splicing a dog and a robot, Roxie can be made to follow you. Unlike other companions, it is possible for Roxie to die, even when not playing on Hardcore mode. However, she can be revived by creating her again at the X-8 facility.
Unfortunately, Roxie only follows you around the X-8 facility and will not follow you outside of the facility. If you leave the area Roxie will stay near the entrance inside the X-8 facility. The holotape to splice dogs and robots is found on a large table downstairs near the institutional test facility door in X-8.
To create Roxie, upon entering the X-8 facility there will be a hallway to the player's left. Once you go through the door in the left hallway there will be a terminal in which you can use the splicing holotapes. Roxie also does not use the companion wheel, you must talk to her to have her follow you or to make her leave.
The cybernetic canine, gender: female, designation: ROXIE sat in her guard post in X-8. That is, until her "I'm in heat" programming circumvented her "stay" routine and she loped into the Mojave.
There, she ran across Rex at the Kings School of Impersonation. His brain was failing. That was all right, he was still smarter than the Think Tank. The two of them constructed a litter of cyberpups, a small army of Boston terrifiers that gnawed and devoured anything in their path.
There, she ran across Rex, who had been following the Courier, just as she had. They barked for a while, and realized they had a lot in common. The two of them constructed a litter of cyberpups, a small army of Boston terrifiers that gnawed and devoured anything in their path.
Rex is alive and a companion on standby
There, she ran across the corpse of Rex. She dragged him back to the Big Empty and had him rebuilt for company. The two of them constructed a litter of cyberpups, a small army of Boston terrifiers that gnawed and devoured anything in their path.
Rex is dead
Roxie is limited to her bite attack, and does not have the sonic bark weapon the other Big MT cyberdogs do.
Though only a temporary due to her location limitation, Roxie is the only companion in Old World Blues add-on.
She's the only companion who doesn't provide perks to the Courier.
Roxie will not do her "good" ending if you have just had her follow you around, it has to be through at least 1 of the X-8 training missions.
Even though Roxie is marked as a companion, she can be killed by the player in non-hardcore mode.