Jus sum complaints

Curious why you feel that way?

For me, it seems pretty natural because she's literally the only child around his age, the only child period, that he's had regular contact with since the beginning of the manga.
And for her, I suspect it's the same, more or less. For nobility in mangas like this, and old European nobility in real life in general, children are often taught in their home rather than a formal school until they're well into teenage-hood or even adult years.
They'll have contact with other children from Noble households, but it's irregular and depends mostly on social gatherings unless they're already betrothed to each other.

So...in the end, for them to create a somewhat deep emotional attachment so quickly seems rather understandable. Especially when the family has opted to basically adopt him and they have practically zero time away from each other~

I remember life as a child for me, and creating attachments to potential friends was always a quick and easy thing when I was really young...then came middle school, haha ^•^;

Don't worry, she is not that relevant to the story.

No? Interesting.

Is it because this manga doesn't really focus on romance, or is she just not a romantic interest for the future? Either way, I'm happy

Spoiler-ish:
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As far as I read the novel, no love interest. But I didn't finish it, so who knows. It focus on him exploring the world and being an OP slime otaku LOL

I feel like maybe it’s exactly because she’s the only child in the manga, obviously there’s worse ones (an immediate three-way engagement after the Mc saved a heiress and princess) but there’s the fact that in nearly every single one of these isekai manga with young male mc, they hang out with the most influential and powerful attractive females

that makes the mc blush and allows him to woo them with his powers; idk it gets rlly repetitive after a while and you get tired of seeing them all over the place since it’s not even an interesting trope in the first place; there are some really good ones that includes a powerful love interest so we’ll have to see who actually is going to be the love interest since she’s apparently not one. Their relationship seems like something that could be more of a sibling or platonic thing instead of romance.

"an immediate three-way engagement after the Mc saved a heiress and princess"

Hahahaha, seriously. I wonder who that could be about?

That aside, what you're saying is definitely true(〜￣△￣)〜
Personally, I wouldn't mind if this remained a "friendship-only" type of manga where he grows more independent while making healthy connections with others, and continues to take care of his slimes~

I honestly wouldn't mind that storyline!