The island of trees had been a lot smaller when Toz and the cats first entered the Void. And it wasn't weird that such a small piece of unnoticeable wood didn't attract a lot of void beasts. At that point, the group also hadn't learned how to discern what the various spots of light in the distance were. So it was very likely that they had been drifting close to swarms of void beasts who just weren't interested in the island.
However, now that they had spent a lot of time in the Void and gotten used to the environment, Toz and the cats could tell that every single source of light in their surroundings was a star.
No one noticed it at first, or if they thought about it once, they didn't think about it twice. They had entered an area of the Void without void beasts. And since they still had an abundant storage of food, they didn't have to worry about it. But as time passed and the food dwindled, Mindle wasn't the only one wondering where all the void beasts were.
