Spell Absorbing Tattoos

Tattoos cover your body in intricate, arcane patterns.

You can use this item as an arcane focus.

The tattoos can hold 20 charges prior to attunement.  After attunement, the tattoos can hold 20 + spell casting ability bonus (or intelligence bonus for non-spell casters) + proficiency bonus.   The tattoos lose charges at dawn (to a minimum of 0 charges) and exhibit passive effects depending on the total number of stored charges, as defined below.  After attunement, you may make an Intelligence (Arcana) check at dawn to attempt to maintain charges that would be lost; the DC for this check is the 10+ the number of charges that will be lost.

Charge Thresholds

1. When charges are 0 - tattoos appear as inert tattoos.
2. 1 to 5 charges - Tattoos will appear to glow with an aura of Enchantment, Evocation, and Abjuration when viewed with a detect magic spell.  Lose 1d4+1 charges at dawn.
3. 6 to 10 charges - Tattoos emit dim light (equivalent to a candle) - light is easy to hide.  Lose 1d8+2 charges at dawn.
4. 11 to 15 charges - Tattoos emit light equivalent to a 'light' spell - disadvantage on Dexterity (Stealth) stealth in dark locations unless obscured.  Lose 2d6+3 charges at dawn. 
5. 16 to 20 charges - Tattoos emit light equivalent to a 'daylight' spell.  Disadvantage on Dexterity (Stealth) stealth in all locations.  Heavy covering required to shield light.  Lose 2d8+4 charges at dawn

Natural Spell Absorption - Other When a spell of level 1 or higher includes you as a target, roll a d20. On a 20 the spell's magic is absorbed - add the spell's level to the number of charges stored in the tattoos and the spell's effects are cancelled.  On an 18 or 19, some energy is absorbed - add 1/2 the spell's level (rounded down) to the number of charges stored in the tattoos and gain advantage on a saving throw against the spell, or reduce the damage to you from the spell by charges absorbed x d6 (to a minimum of 1 damage x spell level).

Natural Spell Absorption - Self When you cast a spell of level 1 or higher, roll a d20. On a 1, the spell's magic is absorbed - add the spell's level to the number of charges stored in the tattoos and the spell's effects are cancelled. On a 2 or 3, add 1/2 the spell's level (rounded down) to the number of charges stored in the tattoos and grant advantage on a saving throw against the spell, or reduce the damage from the spell by spell level x d6 (to a minimum of 1 x spell level).  On a 20, if there are any charges stored in the spell absorbing tattoos an Arcane Flare occurs - Expend 1 stored charge to add an additional 1d6 force damage to a spell attack.

Overload - If absorbing a spell would bring the total stored charges to greater than the maximum, roll a d20.  If the number rolled is lower than the additional charges needed to safety absorb the spell, an overload occurs - all charges are immediately expended in an arcane explosion that expands to fill a 30-foot-radius sphere centered on you.  You may also trigger an overload by using an action to make a DC 17 Intelligence (Arcana) check.  After an overload, you loose attunement to the tattoos if you were attuned,  and for 1d4 weeks no features of the spell absorbing tattoos can be activated nor can they be used as a spell focus.

You have a 50 percent chance that the absorbing tattoos themselves shield you from the explosion. If you fail to avoid the effect, you take force damage equal to 16 × the number of charges released. Every other creature in the area must make a DC 17 Dexterity saving throw. On a failed save, a creature takes an amount of damage based on how far away it is from the point of origin, as shown in the following table. On a successful save, a creature takes half as much damage.

Requires Attunement.  A character unaware of the details of the tattoos must make a DC 20 Intelligence (Arcana) check after a short or long rest to attune.  A character familiar with the tattoos reduces this DC to 15.  Two successive DC 10 Intelligence (Arcana) checks will reduce this DC by 2.  Once attuned, the tattoos no longer exhibit the Natural Spell Absorption abilities and instead exhibit the following; an Overload can still occur.

Controlled Spell Absorption Once attuned, when a creature includes you as a target to a level 1 or higher spell that you are aware of, you may use your reaction to attempt to absorb the spell.  Make an Intelligence (Arcana) check against a DC of 10 + spell level - on a 20 you absorb the spell's energy, per the effects described above; on any other success, add 1/2 the spell's level (rounded up) to the number of charges stored in the tattoos and gain advantage on a saving throw against the spell, or reduce the damage from the spell by charges absorbed x d10. 

Spell Siphon - Your own spells no longer have a chance of absorption but you may attempt to siphon the energy of a spell you cast that fails to hit.  If you miss a targeted spell attack, you may use your reaction to make an Intelligence (Arcana) check against a DC of 20 + spell level.  On a 20, spell is fully absorbed - add the spell's level to the number of charges stored in the tattoos and the spell's effects are cancelled.  On a success, some of the energy is retained - add 1/2 the spell's level (rounded down) to the number of charges stored in the tattoos. 

Arcane Blast - When you hit with a spell attack or melee attack, you can expend 1 charge to deal an extra 1d6+1 force damage to a target.  At higher levels - you may spend additional charges, up to a number equal to the highest level spell slot you can access, to add 1d6+1 force damage per charge.  For example, a 3rd level Wizard could spend up to 3 charges (1 charge base + 2 charges for access to level 2 spells) to deal an additional 3d6+3 damage.  

Channel - If you are a spellcaster , you can convert energy stored in the tattoos into spell slots to cast spells you have prepared or know. You can create spell slots only of a level equal to or lower than your own spell slots, up to a maximum of 5th level. You use the stored levels in place of your slots, but otherwise cast the spell as normal. For example, you can use 3 levels stored in the tattoos as a 3rd-level spell slot.  There is a chance of feedback - make a DC 15 Intelligence (Arcana) check; on a failure, the spell is cast but the caster also takes the spell level converted x d6 damage.

Notes: Damage: Force, Bonus: Saving Throws, Bonus: Magic, Damage, Damage, Combat