Runic Spellcarving

How to make Spellcraft Runes 

Outside of combat you can etch a Spellcraft Rune onto a weapon, shield, Armor or Spellcasting Focus, a Spellcraft Rune is created by channeling a Spell and corresponding spell slot into the weapon, the spell and spell slot that is channeled are permanently un-usable until the etching is removed, this process takes up full concentration and takes an hour to complete. The Spell being channeled into the Spellcraft Rune may only be a spell of cantrip level, 1st level, 2nd level, 3rd level, 4th level, 5th level, 6th level or 7th level. Important to note that 8th and 9th level spells cannot be etched into a Spellcraft Rune under any circumstance as the power will cause the weapon to be destroyed and render any previous etchings to disappear.   

The maximum Spellcraft Runes that a single weapon can have is Six, a shield or armor can have up to four total Spellcraft runes, whereas a Spellcasting focus can only hold three total Spellcraft Runes. Only spells that deal damage or affect an enemy (that are not reactions) can be etched onto a Weapon, while only spells that are taken as a reaction can be etched onto a Shield or Armor piece, whereas a Spellcasting Focus can be etched with a spell that takes either a bonus action or full action. 

Spell slots used to make a Spellcraft Rune cannot be regained by any mean besides either removing the Etching by reforging the weapon, shield, armor or spellcasting focus at a blacksmith or using the blacksmithing tools, or by destroying the weapon, shield, armor or spellcasting focus, as well the spell that has been Etched into the item cannot be cast by any other means while it is etched into an item. When the item is reforged or destroyed the access to the spell and the spell slot is instantly regained.

How Spellcraft Runes work

When a Weapon Etched with Spellcraft Runes hits a target and deals damage or a Spellcasting Focus etched with Spellcraft runes is used to cast a spell that deals damage to or succeeds in affecting a target, for each individual Spellcraft Rune you roll one D6 dice,  if the dice lands on 2, 4, or 6 then the Spellcraft Rune Activates and the spell that is contained inside the Spellcraft Rune will use the weapon or spellcasting focus as a catalyst to cast the spell immediately. When the spell is cast it automatically hits for one third of its maximum damage and the area of the spell only encompasses the target that was hit (if the spell has any secondary effects such as applying blindness/prone/charmed then the target makes the saving throw that is required by the spell with disadvantage). 

When a you are targeted, attacked or are put in danger by any means while wearing a Shield or Armor that is Etched with Spellcraft Runes, for each individual Spellcraft Rune you roll one D6 dice, on a 1, 3, or 5 the Spellcraft Rune activates and is cast using the shield or armor as a catalyst for its full effect and if the target of the reaction would roll a saving throw, instead they do not and are affected for the maximum of the spells effect.