+2 to Constitution due to thicker flesh and lack of nerves

Your lungs are gone but you’re still here, you have no need for breathing due to your summoned nature

You inherited magic from your original caster, cast these spells once per long rest

You are undead and something’s hurt more than others, you are vulnerable to Radiant, Fire, and force damage types

As an undead some forms of damage hurt less or not at all, you are resistant to poison and immune to necrotic due to “Undead Healing”

You can’t heal under normal circumstances, healing potions dont work on you and you can only be healed with necrotic magic (you gain half of the damage you would have taken amount of HP)