Millie/Relationships

Lin and Joe
It is clear that Millie loves both her mother and father, as she happily ran up and hugged them while visiting for the Harvest Moon Festival.

However, she can get aggravated with them due to their behavior towards Moxxie primarily, and is not afraid to stand up to them, along with finding their scolding of her bluntly violent tendencies to be unfair. In the aftermath of her confrontation with Striker, she is not beyond speaking back to her parents.

Sallie May
It is believed that Millie has a typical sibling rivalry with her sister. Millie is a bit miffed over how Sallie May claims to technically not have a neighborhood headcount since the latter seems to be better at hiding bodies, as Sallie tells her in a sing-song voice in The Harvest Moon Festival. Millie also got really annoyed with her sister when Sallie May claims Moxxie would never get their parents respect and how she bet on Moxxie dying in the games.

Moxxie
Moxxie is Millie's husband and co-worker. They have a positive relationship and both adore each other. Moxxie even dedicates a song called "Oh Millie" to her, which can be seen at the end of the pilot. The two are very affectionate and passionate with each other, and often defend each other from accusations.

Millie is also very protective of Moxxie. In Spring Broken, when the Catfish Monster tried to eat a drunk Moxxie, Millie rushed to his rescue and single handled killed the creature. In The Harvest Moon Festival (episode), when she saw that Striker was about to strangle Moxxie, Millie was blinded with rage and stabbed Striker multiple times in the back.

Despite her protectiveness of Moxxie, she seems to at least slightly enjoy teasing him, as seen in the Pilot when she asked Moxxie if he was "trying to crush Blitzo's dreams".

Blitzo
Blitzo is Millie's boss. He is the founder and manager of Immediate Murder Professionals. Millie works as his bruiser alongside her husband, Moxxie, who is his weapons specialist. Millie seems to not mind Blitzo's invasive actions and appears to like her boss. She does sometimes tease him herself such as when she told Striker he was Stolas' "boyfriend".

Loona
Loona and Millie don't seem to get along that well. As in the pilot, Millie can be seen flipping Loona off after Loona insults Moxxie while she growled at her menacingly. In later episodes, Millie usually refers to Loona as "our Hellhound" or "[Blitzo's] Hellhound", which irritates Loona and seems to imply that Millie thinks of Loona as a lesser being compared to her due to Loona being a Hellhound and Millie an Imp, which is ironical since both their species are in the lowest-ranking tier of the hierarchy system.

In Truth Seekers Loona does show some form of concern when Millie started crying uncontrollably after Moxxie is captured along with Blitzo by Agents One and Two. Loona tries to warn Millie that saving the duo was going to be dangerous but was forced to give into Millie's demands and the two women work together in infiltrate D.H.O.R.K.S.. Loona and Millie fought well together, and Loona complimented Millie saying that she is quite agile, yet she also called Millie an "old lady" despite Millie's protests that she is only around five years older than Loona.

Eddie
Millie did not seem to mind being insulted by him, but she drew the line when Eddie starts degrading Moxxie because she knows that Moxxie is more sensitive than she is.

Striker
Initially, Millie had a cordial relationship with Striker who was working on her family's farm as a ranch hand. However, this becomes antagonistic when she finds him trying to kill Moxxie and furiously stabs Striker repeatedly in the back. She refers to him afterwards as a "brown-nosing cocksucker", and she also vocalizes the fact that he was an assassin to her parents since they hired him in the first place. Millie/Relaciones