From Ars Magica
A Lich is a summoned creature with spellcasting ability.
The lich is an archmage that cheated death through forbidden and old magic, causing him to rise as an undead.
The lich is a levitating mage that will follow the summoner and attack mobs nearby. It attacks by casting Arcane Bolt at the target.
When seeing an enemy, the lich will cast Magic Shield on itself to grant it additional magic resistance.
The lich burns in sunlight.