Knowledge of Attaining Lichdom

A powerful undead or fiend has granted you the knowledge of how to become a Lich. Work with your DM to procure a method for attaining Lichdom, for it is not the same in every world. It must include two steps: Creating a Phylactery and Preparing a Potion of Passing.

Once you have crossed the border between life and death, you gain the following benefits:

• You gain proficiency in Constitution, Intelligence, and Wisdom saving throws, unless you already had those proficiencies. 
• You gain resistance to Cold, Lightning and Necrotic damage.
• You gain immunity to Poison; Bludgeoning, Piercing, and Slashing damage from Nonmagical Attacks.
• You gain truesight out to a range of 120 ft.
• You can cast imprisonment once a day, ignoring any material components. When you cast the spell, you can choose to instead trap the target's soul in your phylactery.
• If your phylactery remains intact, when you drop to 0 hit points, you don't make any death saving throws. Instead, your body crumbles to dust, leaving all your items behind. You then reform within 5 feet of your phylactery within 1d10 days.