Nether Star

Nether Star

The Nether Star is a vanilla item obtained by killing the Wither boss.

In Thaumcraft 3, you need it to craft:

These recipes consumes the star, which means you need to spawn and kill the Wither multiple times to obtain the item again for each recipe you want to complete.

The Nether Star can also be used to research items containing the Alienis and Purus aspects. However, due to its rarity, this is clearly not recommended.