WARNING: The following contains spoilers for Episode 7 of The Slime Diaries, "Here Comes the Demon Lord!" now streaming on Crunchyroll.
The spin-off of That Time I Got Reincarnated As A Slime, The Slime Diaries, is all about the day-to-day life of Rimuru Tempest and his friends in the town that they founded together. At times, it runs parallel to the timeline in the original anime, meaning that there are small moments of crossover between the shows. This makes Milim the Demon Lord's appearance in Episode 7 somewhat unsurprising, but still an interesting addition. What's so great about her role in The Slime Diaries is that it shows Milim being surprisingly normal.
Milim's aggressive and confrontational attitude takes up a lot of her scenes in That Time I Got Reincarnated As A Slime, so it's nice to see her character shed that persona and open up to being more content and laidback. The Slime Diaries gives Milim a chance to shine in a way that the original anime hasn't so far. This is a version of her that not only accepts mundane, day-to-day life but is actually excited by it.
In Episode 7, Milim the Demon Lord arrives in Tempest, though her entrance is shown in a much more casual, silly way than in the original anime. Immediately after her dramatic entrance, Milim changes into a completely different outfit and state of mind. She falls fast asleep after eating to her heart's content and is dressed much more conservatively than her normal outfit. From the very beginning of the episode, the new Milim is clearly apparent.
The rest of her day is filled with relatively normal, low-key activities that seem a little uneventful for a Demon Lord. She gets her carrots cut up into little stars by Shuna, spends time petting Ranga, eating snacks until she passes out again, and reminisces with her old friend Gabiru. Milim even sits and watches Geld as he works, entranced by why he spends his time doing meinal labor when he's so powerful that he could do whatever he wants. Seeing Milim in such a state of contemplation is a totally new thing and is a great shift in her character that's, so far, only been revealed in The Slime Diaries.
This "normal," more subdued version of Milim is a pleasant new perspective of her character. Normally, Milim is always bored, so seeing her being content with predominantly boring activities means that her outlook can change. While this version of her may be exclusive to The Slime Diaries, it's a refreshing change of pace when we're so used to the catastrophe that she normally is. Maybe it's because she's finally found a friend in Rimuru, or maybe because it's weird for her to slow down, but the end result is a new side of Milim that is much more agreeable.