Sundered Mind

Through intensive meditation you have achieved greater clarity and focus allowing you to cast a spell while maintaining concentration on a previous spell

• Any attempt to cast a second spell while concentrating requires a spellcasting check with a DC of 10 + the combined level of both spells. A failed role causes the original spell to drop allowing the new spell to work as normal. A critical failure causes the original spell to drop as well as making the new spell backfire dealing 1d10 + the spell's level in psychic damage to the caster.
• Using this feat to cast two concentration spells requires the caster to make a spellcasting check (DC of 10 + the combined level of both spells) at the start of each of their turns as long as they hold dual concentration. Failure causes both spells to drop. A critical failure causes the caster to gain 1 point of exhaustion. Alternatively, the caster can choose to drop either or both of the spells as a free action.
• Constitution saving checks made while concetrating on two spells are rolled with disadvantage regardless of other modifiers.
• Attempting to cast a third spell while dual concentrating causes both spells to drop.