Tandem Algiz Uruz

Whenever a caster casts this spell, they start the tandem spell and it is required for another creature within 5ft. to cast the same spell at the same level within 1 minute to complete the spell and attain its effects. If a creature hasn't completed a tandem spell at the start of their turn, they must use their bonus action on their turn to continue the spell.

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"This spell can be cast in two different ways, Engrave as a setup or Reactive as a reactivation"-Novah

Engrave. You magically engrave rune(s) into a willing creature within range, as you bend the weave of magic, burning the runes formed into their skin permanently "outcome of procedure may wary between hosts"-Fred. The spell must be cast under direct moonlight. While the spell is cast the creature takes 1d6, then 1d8, then 1d10 fire damage as the spell progress'. 

For the duration, whenever the creature would take damage, that creature can use their reaction to reduce the damage by an amount equal to twice their level. For every 5 damage blocked this way, a creature may add 1d10 of the triggering type to their next damage roll, made within a minute. After a creature has spend 5 reaction this way, the spell ends for that creature.

Reactivate. Choose 5 willing Engraved creatures within range, reactivating the properties of their magical runes. For the duration, whenever the creature would take damage, that creature can use their reaction to reduce the damage by an amount equal to twice their level. For every 5 damage blocked this way, a creature may add 1d10 of the triggering type to their next damage roll, made within a minute. After a creature has spend 5 reaction this way, the spell ends for that creature.