Wand, artifact
The Asthresis Crystal is a powerful crystal with an infinite amount of energy that can be used as a focus for a spell, or the energy can be sapped and used as a battery.
If used as a focus for a spell, the spell is automatically used at whatever level is maximum for that spellcaster. for example, if someone tried to cast a level one spell, but their highest level spell is level 3, the level one spell is cast as if it is level three.