Vault of Souls

When you cast this spell, you immediately drink the blood of someone who has died within the last 15 minutes. By doing so, you absorbed their soul, preventing them from traveling to their afterlife. Instead the soul travels to an extra dimensional space within yourself. While in this space, the soul is able to hear and see what you experience, however it cannot interact with the outside world. You are able to freely communicate and mentally shape the extra dimensional space the souls resides in. Casting this spell again can allow you to inprison another soul in the same space, or free any number of souls from this space. 

If you die while there are souls within this extra dimensional space. Your body, upon death, explodes dealing 1d4 force damage in a 5ft radius centered on you, as blood and gore splatters everywhere from the souls escaping from the space inside you. Spells such as deathward or other similar spells prevent this effect from happening. 

When cast using a spell slot 3 or higher, you can absorb two additional souls for each slot above the original.

When cast using a spell slot 5 or higher, you extend the radius in which you can absorb souls by 15ft for each spell level of 5 or higher.