Soul Shards 1

Soul Shards is a mod created by ShadwDrgn that allow you to create an item called Soul Shards that allow you to capture the 'souls' of the mobs you kill. These Shards can then be placed into a Soul Cage, a block that acts as a Vanilla Mob Spawner. The Soul Forge is a special block that corrupts metals and diamonds when fueled by Corrupted Essence - an imperative process in the creation of Soul Shards.

Not only can Soul Cages spawn mobs normally unavailable in Vanilla Minecraft, but when reaching higher tiers, (dependent on the amount of souls the Shard has captured) can spawn mobs at higher rates, and even ignoring light levels.

The souls of most Vanilla mobs, passive or hostile, can be stored in Shards. However, Villagers, Iron Golems, Snow Golems, Squids, the Ender Dragon, the Wither, and all Twilight Forest mobs CANNOT. be stored in Shards. On the other hand, all Thaumcraft 3 mobs, (Wisps, Angry Zombies, and Firebats) CAN.

Important Note: Witch souls can be captured even with their apparent relation to villagers (who's souls cannot be captured).

Trapping Souls
In order to capture souls with your Soul Shard, you must place the Shard on your hotbar. Next, find the mob in which you want to 'tie' the Soul Shard to and kill it. Your Soul Shard will now be linked to that mob type and will only gain souls by killing that mob, e.g. if you want an Enderman Soul Shard, you must kill an Enderman.

You can also capture souls by right-clicking on a Vanilla Mob Spawner with a Soul Shard in your hand will destroy the spawner and add 200 souls to the Shard. Note that the shard must already have at least one of the mob's soul inside for you to be able to right click a spawner.