Stake Hurlers are very effecive siege weapons which are only available to the Evil faction in Stronghold Legends. They cost 250 gold and while this is relatively expensive they do provide fantastic benefits.
Stake Hurlers don't in their own right do a lot of damage to most units in terms of their health, but they do repeatedly knock troops back sending them flying backwards.
Persistently doing this however can not only provide more time for your units to kill these enemy units but also to keep depleting their health at the same time.
All of this makes Stake Hurlers extremely effective from a heightened advantage against the enemy.
This will obviously lengthen their range and if you are attacking from a heightened position behind your own walls, this provides an even bigger bonus because the enemy cannot attack you easily, and you can defend yourself with multiple layers of defences, including Archers and other ranged units.
Stake Hurlers can also fire over castle walls and gatehouses, making them very useful as both siege weapons and defensive fortifications within your castle. You can use them to wipe out enemy units before they even reach their own castle walls, although you must be careful to ensure they are well protected against other enemy units who may creep up on them. Men-at-Arms can also do a lot of damage with their initial Javelin attack as well.
Note however that Stake Hurlers cannot actually defend against aerial attack, or attack any aerial units in any way. This therefore makes them extremely vulnerable to aerial attack and fire or Ice from Dragons. Note that while Ice and freezing by the Ice Queen or the Ice Dragon does not actually freeze the Stake Hurler, it does damage it instead.
You will need 250 gold as well as 1 peasant from the campfire before you can recruit a Stake Hurler.