Countless hours have been spent training your mind to maintain focus on concurrent incantations, taxing as the process may be.
- If you attempt to cast a spell that requires concentration while already concentrating on an existing spell, you can attempt a Constitution check (DC 10+Spell Level) to maintain concentration on both spells simultaneously. If you fail this check you can't cast another concentration spell in this turn.
- If you take damage, you must make a single concentration check (constitution saving throw) at disadvantage, on a fail, both spells are lost. (Works with War Caster)
- You can't attempt to concentrate on the extra spell if the spell you are currently concentrating on is the same spell you want to cast.
- You can use this feature once per short rest or long rest(resets on both,). If you have already used this feature and you want to attempt to use it again you can try to extend your tired mind. If you fail the Constitution check mentioned in the first paragraph while attempting to use this feature again, you gain one level of Exhaustion and you can't use this feature again until a long rest. If you succeed on the Constitution check, you may concentrate on both spells simultaneously. If you lose concentration on one of these spells you gain two levels of Exhaustion, you can’t move or take action until after your next turn and you can't use this feature again until a long rest.
Monstrous Compendium Vol. 1: Spelljammer Creatures
Frozen Sick
D&D Beyond Basic Rules
Basic Rules (2014)
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