Headcanon that Natsumi (my oc) and Diablo became friends through floral arranging. Princess Natsumi became one of Rimuru’s subordinates well before Diablo and she's in charge of agriculture because she was a college graduate in horticulture in her old life. So, naturally, Natsumi also did the vast majority of the floral arrangements around Rimuru’s Government Building as she had to take floral arranging classes for her degree. Diablo took a fascination in how intricate and gorgeous each arrangement was and thought learning to do arrangements could be a good way to earn Rimuru’s approval. So one day, Diablo asked Natsumi to teach him how to floral arrang. Natsumi was absolutely over the moon that someone was wanting to take part in her special interest, especially someone as cool as Diablo. She happily agreed. Diablo had to admit, Natsumi's excitement was adorable. As Natsumi taught Diablo, the two got to know each other and Diablo, over time, felt a feeling he had never felt before. Familial love. Natsumi naturally viewed Diablo as an uncle figure pretty early on and she's naturally a very loving and kind individual. Diablo hadn't experienced such love and kindness in all his existence. So it was only natural that Diablo would view Natsumi as his niece. And that's how the two basically became family. Diablo is very protective of Natsumi and tries his best to teach Natsumi how to act like a proper princess despite her being a wild child. Natsumi is somewhat clingy to Diablo and will often hide behind him when meeting new people. Natsumi often will yap to Diablo about the special interest of the week and Diablo gladly listens. Natsumi loves to play pranks on Diablo (making deez nuts jokes are her personal favorite). She is also Diablo's personal wingman, often encouraging him to pursue a relationship with Rimuru and giving him tips and insight. Diablo gains a lot of new hobbies thanks to Natsumi such as indoor gardening (which he struggles with quite a bit lol), hamsters (because Natsumi owns a hamster that he immediately fell in love with), and nature walks (usually alongside Natsumi)
