Your Constitution increases by 1.

Your creature type is Undead in addition to being humanoid. You can be targeted by spells and effects that can target either creature type.

You tethered your soul to a singular purpose, as long as you have not completed or abandoned that goal you gain the following benefits.

• If you are below half your hit point maximum, but not at 0 hit points, at the start of your turn, you regain 1 hit point.
• When you are reduced to 0 hit points but not killed outright, you can drop to 1 hit point instead. You can’t use this feature again until you finish a long rest.
• You know the general distance between you and any creature involved in your goal, such as a person you seek vengeance against or someone you pledged to defend. At times this awareness will be stronger than others, it can be affected by proximity, magical effects, and your emotional state. This awareness fails if the creature is on another plane of existence. 

Your body, cold to the touch, no longer carries any vitality. Fortunately, this means it is far less susceptible to toxins. You are resistant to Poison damage and the Poisoned condition.

Your body no longer desires food or water. You do not have to eat or sleep as your bodily functions have ceased, though you still need to take a long rest to recover from exhaustion. During a long rest, you can engage in light activity like reading or being on watch and still get the benefits of it. 

Unfortunately, you cannot be healed by a spell, potion, or magical effect, other than your Relentless Nature trait unless it specifically states that Undead creatures can be healed from its effects. You cannot be revived from death short of a Wish spell.