Atomic Heart

An eldritch bio-mechanical Heart that beats at an erratic and unpredictable pace. When bestowed to a person, the heart implants itself into the receiver's chest and replaces the owner's heart with itself. The heart allows you to better control your precision and power. While attuned to this, you are granted a +5 to all Attack and Damage Rolls made with Ranged Weapons. With the erratic heartbeat, you can't be magically put to sleep. Should the Heart enter an Antimagic Field, it will only be able to grant the user its Atomic abilities and the Archon's Archetype ability.

Erratic Black Heart - The Heart magically produces ammunition for ranged weapons you use, and guard your weapons from damage. You no longer need to reload nor suffer from misfires. This magical ammunition deals an extra 2d10 poison damage to the target. You regain a number of hit points equal to the poison damage you deal. Additionally, this magical ammunition can ignore creations of magical force should you choose. You automatically succeed on, and take no damage from (if any), spells and effects whose DC is 20 or lower.

Erratic Heartbeat - As a bonus action, you can choose to speed up your heartbeat. Doing so doubles your speed, increases your AC by 3, grants advantage on Strength and Dexterity saving throws, and you gain an additional action on each of your turns. That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action. This ability lasts for 1 minute. Once you use this bonus action, you can't use it again until you finish a long rest, unless you spend 1 Indomitable Point to use it again.

Atomic Advent - You add your proficiency bonus to the damage of your ranged weapons. As a Bonus Action, you can build energy within the heart and detonate. All hostile creatures within 1 mile must succeed on a DC 30 Strength Saving throw. A creature has their current HP be reduced by 250 Points on a failure and 150 on a success (as if they had taken damage). After detonation, you must roll a DC 30 Constitution Saving throw or have your HP Reduced to 1 (This Save cannot gain any bonuses such as a Paladin's Aura or Bless, etc.). If you choose to detonate again while at 1 HP, you die. Once you use this bonus action, you can't use it again until you finish a long rest, unless you spend 1 Indomitable Point to use it again.

Archon's Archetype - Your body changes to carry out the will of the Anti-Goddess. Your creature type is now "Fiend", Subtype "Archon". You are granted a +15 bonus to initiative as long as you aren’t incapacitated. You have advantage on initiative rolls. In addition, you can’t be surprised, except when incapacitated by something other than nonmagical sleep. The Heart magically awakens you if you are sleeping naturally when combat begins. Any spells or effects from allies that would harm you or debilitate you no longer will (If you so choose). Any spells or effects from you that would harm or debilitate your allies, no longer will (If you so choose).

Atomic Symbiosis - The heart can't be removed from you while you're attuned to it, and you can't voluntarily end your attunement to it. If you're targeted by a spell that ends a curse, the caster must succeed on a DC 35 Casting Stat Check or go Insane for 1 Year. While insane, you can't take actions, can't understand what other creatures say, can't read, and speak only in gibberish. On a success, the caster isn't insane and your attunement to the heart stops and you die. Should you die, your soul is instantly trapped inside the heart instead, instantly and cannot be deterred otherwise. Should you be revived, the Heart beats again and your soul is returned to your body. Should you be given a new body, the Heart will appear is that body's Heart upon creation. The heart cannot be disabled, suppressed, extracted or be subjected to any spell or effect that would render it inactive.

Legendary Resistance (3/Day): If the user fails a saving throw, they can choose to succeed instead.

Notes: being who was chosen by Cartesia