The Occult Core

The Occult Core is the gem Rundis used to focus his spells. It was his not only his focus but it channeled the collective power of other wizards he worked with to cast the 10th level spell, time loop.

When he died attempting to create The Pocketwatch of Eternity, this core absorbed his magical prowess and some of the the abilities of the other spell casters present.

When used as a spell focus, the occult core can turn equivalent spell slots into each other.

For example, two level 1 spell slots can be turned into a level 2 spell slot, or one level 4 spell slot can be turned into into four level 1 spell slots.

You cannot involve spell slots of level 5 or higher in this process, so no spell slot of level 5 or higher can be created or destroyed to consume or create other level spell slots.

The occult core has also gone through a process to make it pure enough to cast level 10 spells, if enough other spellcasters are present to lend power.