"While skeletons and skeleton warriors are average foot soldiers individually, it is possible to build massively populated troops of them. They are numerously produced, are the main creature produced by the Necromancy secondary skill, and other creature types can be converted into them at Necropolis skeleton transformers."
Skeletons are an undead unit associated with the Necropolis faction as the first tier unit in the video game Heroes of Might and Magic III: The Restoration of Erathia and its two expansion sets, Armageddon's Blade and The Shadow of Death. They can be recruited by a player in possession of a Necropolis town by building a cursed temple for the price of 60 gold per unit. Like all other undead units in the game, they are immune to any and all mind-affecting spells, as well as Bless and Curse, as well as always possessing neutral morale.
While not the strongest of the tier 1 units in the game, the skeleton and its upgraded version, the skeleton warrior, can gain in number quickly until they will massively outnumber other creatures they may come up against. Not only this, but a Necromancer can build the unearthed graves to increase their weekly production by 6 more units, and the skeleton transformer building to convert other units into skeletons. This is a good way to treat random, lower-tier mobs who wish to join you. Because of their sheer numbers, they remain the backbone (no pun intended!) of the Necromancer's armies.
Skeletons are notable for their ability to grow in numbers exponentially as the game progresses, which can actually make them fairly dangerous despite being the bottom-tier unit for their faction. Heroes with a high Necromancy skill can easily meet or surpass the numbers of throngs of the Knight faction. Though weak like other first tier monsters, they have a speed stat of 4 and will hit for around as much damage as Walking Dead, the next-tier creature for the Necromancers (skeletons hit for 1-3 damage, walking dead for 2-3), though they are weaker defensively.
A clever Hero will use their available skeletons during offensive attacks against creatures that they can be likely to kill or cripple, in order to avoid disastrous repercussions such as painful retaliations.
Upgrading your skeletons to skeleton warriors is debatable as a good idea for an undead army. This is because while it will increase their attack, defense, and speed stats and will only cost an extra 10 gold per unit, any hero that knows the necromancy secondary skill will receive new skeletons after every battle, which will mean to keep increasing their numbers you will need to have two spots for them to occupy out of only five available slots. While an army that has skeleton warriors and no slots for regular skeletons will obtain skeleton warriors instead, they will only receive two-thirds the number that they would have received otherwise. Heroes that remain near a Necropolis town that they own can of course follow this up by returning to town to upgrade the stack to warriors before continuing on.