You have been infected with a symbiotic organism from the mortal realm. With immense arcane power the organism promises you abilities if you swear to host it. This being wishes to experience life through your eyes, how you would, expecting you continue on with your life as you normally would.
Expanded Spell List
The Symbiote lets you choose form an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.
1stcure wounds, false life
2ndaid, lesser restoration
3rdaura of vitality, mass healing word
4thblight, death ward
5thgreater restoration, reincarnate
If you take the Pact of the blade at 3rd level, the weapon you create looks organic, the blade is made of bone and the hilt is covered in rough skin. If it is a bow the bowstring is sinew and the arms of the bow are cartilage.
If you take the Pact of the chain the familiar you are given is a stirge.
Starting at 1st level the symbiote offers you some protection, your base AC becomes 10 + your dexterity modifier + your charisma modifier.
Starting at 6th level you can use an action to spend up to your charisma modifier of hit dice to regain health. Once you use this feature you can’t use it again until you finish a long rest.
Starting at 10th level you become proficient in constitution saving throws and gain resistance to non magical bludgeoning, piercing and slashing damage, and become immune to poison and disease.
Starting at 14th level, when you are reduced to 0 hit points, but not killed outright, you can drop to 1 hit point instead and can as a reaction use the Symbiotic Life feature. Once you use this feature you can’t use it again until you finish a long or short rest.