+2 to str and +1 to another ability score of your choice

Your body is naturally armored providing an AC of 12 plus your strength and constitution modifiers, you have disadvantage on stealth and slight of hand checks; and because of the nature of your construction you don’t need to eat, drink, breathe, or sleep you are immune to poison and disease you also do not feel the effects of extreme temperatures and pain is extremely dulled you can also fit one creature at least one size category smaller than you inside your chest cavity.

Your unarmed strikes deal 1d4 bludgeoning or slashing damage at 1st level this increases to 1d6 at 3rd, 1d8 at 5th, 1d10 at 7th, and 2d6 at 10th (this is still affected by your size) you also gain proficiency in intimidation and can use strength instead of charisma for it.

You cannot be put to sleep by any magical or non magical means and if you drop to 0hp or enter an anti magic field you drop unconscious until a dc 20-con arcana check succeeds on you which can be attempted once per hour if you are not restored within 3 hours your soul unbinds and you die leaving an empty suit of armor in order to take a long rest you must spend 4 hours in low activity to gain the effects of a long rest.

If you spend 1 long rest in contact with another piece of armor you can copy its magical effects to yourself you may have 1 set of armor, 1 set of gauntlets, 1 pair of boots, and one helmet copied to your body at a time and doing so renders the original non magical and changing effects destroys the original effect.

You are immune to any magical effects that would change or alter your body besides the enlarge/reduce spell.