Lich (Public/Peer Review)

Lichdom is a dark form of magic where you sacrifice an unwilling soul to lengthen your own life and bind said soul to an important object, this results in what's known as a phylactery. A phylactery adds 10 years to your own life per sacrificed soul. Playing a Lich would be challenging to moral players as sacrificing a soul tends to be seen as a bad thing by most people, so Liches would most likely be part of evil or immoral campaigns. To play a naturally good Lich you may have to embed some sort of rules that your character would abide by such as you may only kill in self-defense or you may only take souls from those who kill or hurt others. A Lich is a Wizard subclass whose rules may differ a bit from the scripted abilities above, and this subclass assumes that you are just a beginner or a weaker version for balancing reasons. 

Life Steal

At level 2, when an enemy dies within 5 ft of you you may use a Reaction and spend one from your highest spell slot to heal 1d6 health. (At level 5 you heal 1d8 up to 10 ft: level 10 1d10 up to 20 ft: lvl 15 1d12 up to 40ft: and at level 20 1d20 up to 80 ft)

Basic Phylactery

At level 2, the next time you kill an enemy you craft a Phylactery, which will hold souls for you to cast spells and heal with. When a creature dies within the range specified in the Life Steal ability and you don't use Life Steal the soul will be held in this item (maximum 25) and you may use 10 souls to replace a spell slot equal to or under level 3.

Advanced Phylactery

At level 6, you upgrade your Phylactery to a more advanced version, this will hold up to 50 souls and you may use 5 souls to replace a spell slot equal to or under level 3 and 10 for levels 4-6.

Master of Death

At level 10, you deal an extra 1d8 Necrotic damage to enemies who have taken damage (Lvl 15, 1d10 damage: Lvl 20 1d12 damage)

Perfected Phylactery

At level 10, you upgrade your Phylactery to a perfect version, this will hold up to 100 souls and you may use 1 soul to replace a spell slot equal to or under level 3 and 5 for levels 4-6 and 10 for 7+.

Basic Immortality

At level 14, when you use your Life Steal Ability you can choose to instead of regaining health you may add 1 more year to your lifespan but if you do use this you lose your movement option on your next turn