@Metasepia It’s not that there aren’t any people in her country. She lives amongst humans, who she saved from scary monsters once upon a time. Now, those humans built her a castle, worship her and revere her as their god, but they’re also very afraid of her due to her terrible power. But because they worshiped her, they bring her offerings, like all the food she’d ever need to eat. Except all that food is just raw fruits and vegetables. There’s no meat, and no cooking. And because there’s no cooking, she doesn’t get the opportunity to run into these people and talk with them. She doesn’t even have any subordinates (which is why she’s so lonely), at least not until the Demon Lord Summit.
At that time, the ‘Ten Great Pillars of the Demon Lords’ became ‘Octogram’ (in other words, from ten to eight). Demon Lord Rimuru was added in. One of Demon Lords was killed. And the remaining two Demon Lords and both their countries full of citizens under their rule became Milim’s subordinates and subjects. And her once monotonous, lonely, lazy, and agonizingly monotone life became fast paced, hectic, tedious, and filled with too much work to do. But she was really glad to finally have more company.