Akki's Magnum Opus

An uncut and weathered green gemstone that pulses with faint green light. It hangs on an unassuming necklace. This stone was created by a long passed necromancer who toiled over it for more than 500 years. It is the accumulation of his life's work and contains very advanced magic, but is very difficult to use.

Leveling: As the player researches and experiments with this item it gains levels. Many levels have specific requirements that must be fulfilled. Due to the deep and complex magic woven into this item the level is determined by the user's familiarity with it and resets to level 1 if it is attuned to a creature. It is up to the DM to determine if leveling requirements should be revealed to the player, but it is suggested that they give no more than clues. Level requirements must be made in order. Additionally, the DM may decide to have the item consume more than one attunement slot at higher levels to maintain item power balance.

Level 1: Undying - If damage would reduce the wearer's hp to 0 the wearer makes a CON saving throw with a DC equal to 5 + the damage dealt. If the Wearer is at 1 hp before the triggering damage the player makes this save at disadvantage. If the wearer succeeds on the save they drop to 1 hp instead and remain conscious.

Level 2: Imbue Life - The user can use this stone to cast Revivify without expending a spell slot. The material components for the spell are still required. After using this feature they cannot do so again. At the end of a long rest the user may expend a spell slot of 3rd level or higher to recharge the stone, regaining the ability to use this feature.

Improved Grim Harvest - If the user kills a creature with a 1st level spell or higher they regain hp equal to 2 times that spell's level. If the triggering spell was a necromancy spell they gain hp equal to 5 times the spell's level instead. If the user kills a target with a necromancy cantrip they regain 5 hp. This effect can only be used once per turn and doesn't work on constructs or undead. This skill does not stack with the effects of the Wizard School of Necromancy's 3rd level skill Grim Harvest. 

Level 3: Soul Warden - When a creature within 30 feet of the user dies, the user may use their reaction to capture the creature's soul in this stone. Creatures targeted by this ability can't be resurrected and undead, constructs, and creatures with a INT bellow 5 cannot be targeted by this ability. An attuned user may cast Animate Dead at it's lowest level without expending a spell slot, instead expending 1 stored soul per raised undead.

Thrall Mastery - When the user has undead under their control they may use their action to give more precise, and complicated orders. Additionally, the user can give multiple orders to different undead in the same turn. This effectively allows them to take full control of their thralls.

Level 4: Profane Aura - While this stone holds 10 or more souls you emit an aura that enhances your undead army. The Aura has a 10ft radius and increases by another 5ft for every additional 10 souls stored in the stone (30ft maximum).

Loyal Thralls - Undead under your control that are within the aura gain a +2 bonus to AC. In addition, whenever you are targeted with a melee attack and you have a thrall within 5ft of you, you may use your reaction and the thrall's reaction to force the attack to target the thrall instead. You must choose to use this ability before the attack is rolled.

Levels 5+ TBD

Notes: The user must be a Wizard (the DM may restrict it's use to wizards of the school of necromancy). To attune to this item the player must perform a 10 minute ritual. At the end of the ritual they sacrifice all of their hp, but may use the first ability of the stone to attempt to feign death. If the save fails they enter an unstable state and make death saving throws as normal.