Hey there, 

I wanted to create a Feat that adds Spell Slots, but the "Spell Slot Increase" modifier can't be created because the modifier subtype dropdown doesn't contain any values.

I'd expect there to be a list of Spell Levels, but instead it's empty, causing creation to fail due to a missing required field.

That's it. Thanks and best wishes, 

J

The current Homebrew system does not support modifying certain core game mechanics like number of Spell Slots.

The best workaround I can currently think of is to give your homebrew Feat some charges. You will just have to remember that you have extra Spell Slots to tick off in the Feats section of the character sheet in addition to the regular Spell Slots in the Spells section.

For example, you can create a Feat called "Spell Slot 1st Level: 1" and it will have one charge, "Spell Slot 1st Level: 2" will have two charges, etc. To save time, if you only need an extra ten slots for any given spell level, you only need to create up to "Spell Slot Xth Level: 4" and then mix and match the Feats to get the desired amount of Spell Slots. So if you need eight extra 9th Level Spell Slots, you add "Spell Slot 9th Level: 1", "Spell Slot 9th Level: 3", and "Spell Slot 9th Level: 4" to your Feats.

Feats do not have “charges” as such. You would need to create an Action with limited uses instead.

Thanks for the feedback. I already have a workaround, I was just wondering about the incomplete option.
Feels like it should either be fixed or removed.

Sorry for the necro, but the option is apparently a dummy option for the Book of Exalted Deeds. Specifically the feature Enlightened Magic. A feature that allows Paladin & Cleric spells to be cast at one level higher than the spell slot used. From what I have gathered, the functionality was just never implemented, but the dummy feature was left in.