Fiendish Vigor (2024)

Let me try to clarify the logic here.

Magic Initiate gives me a Warlock spell that has been already prepared (that's always there). So now I have this spell, and under the Pact Magic rules, it becomes a Warlock spell for me. That means the spell should always use my highest-level spell slot.

So what does Fiendish Vigor do? The rules clearly state: “You can cast False Life on yourself without expending a spell slot.”

I’m casting a Warlock spell, which under the Pact Magic rules is always cast using my highest-level spell slot. Fiendish Vigor simply allows me to cast it without actually expending that spell slot.

What I don’t understand is why you believe that the defining feature of Warlock spellcasting somehow disappears when a spell is cast without expending a spell slot?

Warlocks are unique spellcasters. Unlike Wizards, Sorcerers, and other spellcasters, their Pact Magic spell slots are always of the highest level available to them.

There was a discussion above arguing that Fiendish Vigor doesn’t allow you to cast False Life at your maximum spell-slot level because Fiendish Vigor itself doesn’t add False Life as a Warlock spell.

Thus, Magic Initiate is what allows us to get around that limitation.

Quote from Dgek >>

 

What I don’t understand is why you believe that the defining feature of Warlock spellcasting somehow disappears when a spell is cast without expending a spell slot?

 

Because the you are trying to apply it to an effect that says "Using a Higher Level Spell Slot ". Ergo, casting without expending a slot by definition fails to meet the criteria, and thus unless you can point to some other explicit language in how you are casting the spell that changes it, everything followed by that qualifier simply cannot obtain.

The Warlock's unique spellcasting feature is specifically tied to the use of their Pact slots. If a pact slot is not used, then by definition the Pact Magic feature does not apply.

Quote from Dgek >>

Warlocks are unique spellcasters. Unlike Wizards, Sorcerers, and other spellcasters, their Pact Magic spell slots are always of the highest level available to them.

There was a discussion above arguing that Fiendish Vigor doesn’t allow you to cast False Life at your maximum spell-slot level because Fiendish Vigor itself doesn’t add False Life as a Warlock spell.

Thus, Magic Initiate is what allows us to get around that limitation.

Your Pact Magic spell slots and what level they are do not matter if you are not actually using them to cast the spell. Whether the spell is a Warlock spell or not does not matter if you are not using your spell slots to cast the spell. The idea that you can somehow use a spell slot without actually using it is not supported by anything in the rules.

This has been pointed out in this thread several times.

Quote from Dgek >>

[...] Magic Initiate gives me a Warlock spell that has been already prepared (that's always there). So now I have this spell, and under the Pact Magic rules, it becomes a Warlock spell for me. That means the spell should always use my highest-level spell slot. [...] 

 A feat, even when gained through a class feature, is not considered a class feature, so a spell gained through an ASI won't count as Warlock spell by default, unless the feat says so (e.g. adding its spells to your class list) or the spell is already listed on your Warlock spell list.

At least is my understanding based on the following information from the PHB: 

Chapter 5: Feats
This chapter offers a collection of feats, which are special features not tied to a character class. [...] Your background gives you a feat, and at certain levels, your class gives you the Ability Score Improvement feat or the choice of another feat for which you qualify.

This example for Wild Shape:

Game Statistics. Your game statistics are replaced by the Beast’s stat block, but you retain your creature type; Hit Points; Hit Point Dice; Intelligence, Wisdom, and Charisma scores; class features; languages; and feats. You also retain your skill and saving throw proficiencies and use your Proficiency Bonus for them, in addition to gaining the proficiencies of the creature. If a skill or saving throw modifier in the Beast’s stat block is higher than yours, use the one in the stat block.

And this information from the Converting to System Reference Document 5.2.1: 

Feats

Feats “Feats” includes the following new and revised elements, which are presented in the order in which they appear in that section.

Feat Descriptions [New Rule]

Feats are now divided into categories, including Origin, General, Fighting Style, and Epic Boon. All feats in this section are new except for the following revised rules.

Ability Score Improvement [Revised Rule]

This rule is now a feat rather than a class feature.

Grappler [Revised Rule]

This feat is revised and is now a General feat.

Fighting Style Feats [Revised Rule]

These rules are now feats rather than class features.