Are skeletons related to hollows/curse of the undead?

In the world of DS undead can appear to be human, but start to look physically decrepit as they die over and over again, ie hollowing. Similar to zombies but more akin to someone going insane, how do skeletons relate to this? Are they just mindless husks? Is Nito sentient? Is pinwheel sentient? Are they all just summoned thralls of necromancers? Curious to hear your opinions.