MK-1, also known as Emkay-One, functioned as a butler droid in the service of Thane Markona at his mansion. When Leia Organa, Luke Skywalker, and Han Solo, members of the Rebel Alliance, found themselves stranded on Hubin, he assisted in their care.
During Thane Markona's time residing on the moon Hubin, MK-1 provided service to him and his daughter Tula at their estate. After Markona permitted the Rebel Alliance refugees, namely Leia Organa, Luke Skywalker, and Han Solo, to reside in his residence, he entrusted Emkay-One with their well-being while he confronted a group of thanrax. Upon Solo's request, Emkay-One prepared and served him a Rodian Splice.
Subsequently, Emkay-One accompanied the rebels when they formally presented themselves to Markona. Upon learning that Tula had arranged a meal for their visitors, he voiced his disapproval, stating that she should not be performing his duties. Following the meal, Organa inquired whether the rooms designated for their stay contained computer terminals, and Emkay-One volunteered to set one up. MK-1 later informed Markona about a thanrax assault occurring at the periphery of the village. Markona instructed Emkay-One to assemble his huntsmen while he and Luke engaged the thanrax.
After the thanrax threat was neutralized, Emkay-One entered Luke's quarters and discovered that he, C-3PO, and R2-D2 were constructing a transmitter. While Luke was surprised to be discovered, Emkay-One revealed that he possessed relevant tools and blueprints in storage, and inquired whether he could offer assistance. Tula became aware of Emkay-One's involvement and subsequently discussed with Luke the potential ramifications of contacting the outside world for Hubin. Despite this conversation, Luke returned to the mansion, instructing R2-D2 to activate the transmitter.
Unbeknownst to Luke, Thane Markona had orchestrated Emkay-One's assistance and was aware of the transmitter, actively blocking its signal. After Luke believed he had successfully activated the transmitter, a Sentinel-class landing craft landed on Hubin. Emkay-One notified Markona of this event, adding that he was unable to determine its identity. Markona met with the shuttle, which had been brought to the moon by the Galactic Empire's SCAR Squadron, who had extracted the rebels' location through the torturing of Sana Starros. Emkay-One greeted the stormtroopers at the entrance of Markona's mansion, overwhelmed by the sheer number of guests he anticipated accommodating.
Being a butler droid, MK-1 exhibited a strong desire to serve, expressing disappointment when others performed his tasks. He readily offered assistance to anyone, even those unfamiliar to him, such as the rebel guests at Markona's residence. He even proposed aiding Luke in constructing a transmitter, a device not typically utilized by Clan Markona due to their isolationist practices.
MK-1 made his debut appearance in Star Wars (2015) 56, a 2018 canon comic authored by Kieron Gillen and illustrated by Andrea Broccardo.