Michael Barrett

"You know, I was having doubts about how strong you guys were. Thanks for proving me wrong."

- Mickey regarding the Sandbox troops in Early in the Mourning

Michael "Mickey" Barrett is a Guardian first mentioned in the episode Insight to the Past. According to the episode, Mickey was McGrath's friend and the latter even considered him the "funniest man he ever met.", indicating that Mickey was a comedic person. Mickey later makes a physical, and more prominent, appearance in the Season 3 episode Soldiers on the Loose, where he is shown to be a very sociable, charming, and confident person.

Mickey spends much of his time with his best friend Bartholomew, as the two fought together during their time in the ONC and later the Guardians. In addition to being a great fighter, Mickey is very protective of his friends' emotional well-beings and tries to do things that are best for everyone. While a little cocky, Mickey cares about his friends and is willing to die for them, in order to secure their safety.

Personality
During his first appearance, Mickey is shown to be a very comedic person, just as McGrath described him as. In Soldiers on the Loose, Mickey is shown constantly making witty remarks with Bartholomew and seems to have a somewhat playful persona. Mickey is also a very strong individual, as shown with his armor permutations. He fights his enemies as if he is playing a game, competing with Bartholomew to see who can get the most kills.

In addition to his skill and humor, Mickey is also very self-confident and friendly. When interacting with the Sandbox troops, Mickey trains them hard but fair, wanting to improve their fighting prowess and stamina. During Heated, Mickey is shown to not tolerate quitters as he criticized Jason for making excuses and argued with Ichabod and Gates for wanting to take a break. In the following episode however, after Dax collapses, Mickey expressed concern over the Reds' and Bues' well-being and allowed Miller and Claire to leave by showing them a hidden sewer passage at DotCom. Mickey was also about to inform the other Sandbox troops of the sewer passage if Claire had not stopped him, showing that he cares for the Sandbox troops.

Mickey also respects and cares deeply for his friends as he showed distraught over McGrath's death and sympathy for Nash. In addition, Mickey is very loyal to his fellow Guardians as he is willing to take orders from Allan and Nash without question and quickly informs them of new information.

Overall, Mickey is a skilled fighter and good-hearted individual, showing respect to those who deserve it and displaying a great deal of confidence without being overly cocky (most of the time).

Bartholomew
Bart is Mickey's best friend and the two are regularly seen together. Throughout Season 3, Mickey and Bart battle together, support each other, rip on one another, and train the Sandbox skirmish troops together. Bart cares for Mickey deeply as he yelled in horror upon seeing Mickey get hurt. Mickey also expressed great concern after Bernard shot at Bart.

In terms of history, Mickey and Bart were initially rivals during their time in the ONC's Combat Division. Being one of the few Elites there, Bart excelled in battle and surpassed many of his peers, which Mickey took notice to. This led the two to compete with each other, which eventually helped them form an understanding with each other and bond. While other humans expressed their prejudice towards Bart, Mickey showed Bart friendship and even learned to understand Sangheili, though he couldn't speak it. In response, Bart learned to understand English.

The two are shown to be great friends and allies.

Trivia

 * Mickey is inspired by the characters of Tex and York from the popular web-series, Red vs. Blue, as well as Han Solo from the Star Wars franchise.
 * Mickey is shown primarily using Covenant weapons, emphasizing his closeness with his best friend Bart and his respect for aliens.