Lich

Liches are a powerful type of undead creature. They are mages that, through the use of Necromancy and Black Magic, have prolonged their lifespan, turning them into powerful immortal beings.

Creation
In, a lich is a mage who seeks immortality, and some use powerful magics to expand their lives. One mage named Celedaen attemts to surpass death by using the Sands of Resolve, an hourglass that must remain on his person until the transformation is completed.

In it is mentioned that the process of becoming a lich involves draining the life force of someone and transferring it back to the lich's body. The Dragon Priests of Skyrim managed to do this by making their servants give their energy to them. However, this is not always the case, as the Dragon Priest Hevnoraak managed to get some of his life force back by transferring blood into his body.

Powers and abilities
Liches are some of the most powerful undead as they are able to cast vasts amounts of spells such as destruction magic, and are able to summon undead such as skeletons and zombies. They apparently can resist magical attacks, and therefore are not to trifled with; extreme caution should be taken when fighting with one. Liches can see those that are invisible, and have an immunity to all weapons besides Mithril and silver, although they are able to be killed by fire. Additionally, they are able to regenerate health when wounded.

Physical appearance
Physically, Liches appear to be undead with decaying skin and bodies. They generally wear robes with a helm and shoulder plates, an amulet, and carry a staff that they use for combat.

Notable liches

 * King of Miscarcand
 * Erandur-Vangaril
 * Lorgren Benirus
 * Areille Jurard
 * All known Dragon Priests
 * Barilzar

Trivia

 * Liches in oddly have red hair, despite being undead for so long.