This mod changes the way that Wither Skeletons behave. In vanilla, there are numerous issues with their spawning, their drops, and it is generally regarded as a chore to grind for skulls. This seeks to remedy that by doing a few things.
1) Adding a wither skull fragment to the drop tables. This is by default worth 1/9th of a skull, and will always drop when a skull has not been dropped.
2) Forcing all skeleton spawns in the nether to be wither skeletons. Vanilla uses RNG to decide if a skeleton will be wither or not, even in the nether. This makes all skeletons spawned turn into wither skeletons, as long as they are in a Hell biome.
3) Removing stone swords from drop tables. These things are annoying to funnel around, and are just completely useless. So, off with them.
4) The immolation blade is also added, which emulates the Skullfire Sword from Avaritia (without costing you an extreme amount.)
The mod also comes with a powerful configuration file, which can change and control almost every aspect of the mod.