In my world, skeletons are a thing. They're raised from existing corpses under the control of their "master".
Obviously, there's magic involved. But I don't want magic to be part of the whole process. Let's say the magician behind the skeletons control is simply acting as a puppet master, pulling strings from dead people's skeletons.
How can these skeletons be challenging and a little realistic?
Bones are kinda resistant, but not that much. I guess the mouth would be full of various infections considering this is a corpse we're talking about.
Let's assume the puppet master can provide them an above-average speed (considering he's the one pulling the strings) so they can hit with a pretty good momentum. The puppet master are also very good war tactician, so the skeletons aren't just empty minds running to the battlefield.
These skeletons can be animal or human skeletons. But obviously, it's easier to find human corpses than grizzly corpses.
Edit : I wasn't clear about the kind of challenge they should be. I'm trying to find ways for a small group of skeletons to put up an okay fight to the "hero", mighty sword-wielding badass. They should represent great dangers to villagers or people with little fighting experience.
I'm okay with answers involving more magic. I'd just like the main idea of "skeleton puppets" to be respected.
About the puppet masters : The puppet master are controlling the skeletons 24/7. They have trained for years and years to master this art. They do not suffer consequences of fatigue/hunger/thirst because reasons (It's a work in progress :p). Let's say each of them can control about 30-40 skeletons at the same time, which absolutely doesn't mean these skeletons are "travelling" as a group. They are usually scattered, because unless there's a specific event happening they don't need to be in such a huge number. There are multiple puppet master and they do work together and communicate using telepathy.