Steadfast was part of a crew of human colonists who had settled on the planet Gliese 581 D in the far future.
When he awoke from stasis, he met the Twelfth Doctor and Bill who told him that the Vardis had killed the entire set-up team. However, instead of listening to the Doctor entirely, Steadfast and a few other colonists armed themselves and decided to kill the robots who they thought were a threat. When two Emoji bots were about to kill Praiseworthy who was crying because his mother was among those killed, he shot the robots to save him, prompting the Vardis above them to attack in retaliation. When two Emojibots were about to kill Praiseworthy, he shot one of the robots, prompting the Vardis above them to attack in retaliation. (TV: Smile)