There is a way to automate Will collection, this will require a few more advanced items that you might not be able to get your hands on early in the game. Using the Sentient sword and a mechanical user (from Extra Utilities 2) as well as some sort of mob farm you can set up a system that will automatically hit mobs with the sword and have them drop Demonic Will.
You will need to check the Mechanical User to ensure the Sword is repaired. This will hit mobs with a sword without you having to lift a finger, you will only need to ensure that the Will is being picked up. To store the Will in a Tartaric Gem, make sure to drop it on the ground and pick it up again with the Gem in your inventory.