[RPG] Are there any broken applications of this homebrew “Overcast” system


I'm considering adding the following homebrew rule variant into an upcoming campaign:


If in dire need, any spellcaster is capable of expending their own life force to enhance their connection to the Weave. This allows them to cast one prepared spell without consuming a spell slot.

When you do so, you must make a DC 10 + Spell Level Constitution Saving Throw. On a failure, you take a number of levels of exhaustion equal to the spell's level immediately after the spell is cast. On a success, you take a number of levels of exhaustion equal to half of the spell's level, rounded up, immediately after the spell is cast. If the saving throw is failed by 5 or more, you take the levels of exhaustion immediately and the spell fails to cast.

You can only Overcast spells at a Spell Level less than or equal to your highest level spell slot plus one, the total of which is no higher than nine.

As items of this nature tend to have unintended consequences, I'm hoping to patch out as many exploits as possible before officially introducing it. What are some of the ways to grossly abuse this mechanic?

Best Answer

Elementals are immune to exhaustion.

Circle of the Moon druids can turn into elementals at level 10. Elementals have immunity to the effects of exhaustion.

The Beast Spells feature of Druids at level 18 allows casters to cast spells while in wild shape.


Druid turns into a fire elemental. Being immune to the effects of exhaustion, the druid could cast extremely high level spells every single turn with no negative side effect. Before the druid leaves elemental form, an ally casts Greater Restoration on the druid, to lower the level of exhaustion from 6 to 5, so that the druid doesn't instantly die.

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