Warlocks have access to this invocation:

Fiendish Vigor

You can cast false life on yourself at will as a 1st-level spell, without expending a spell slot or material components.

False Life is a 1 action spell with a 1 hour duration that does this:

Bolstering yourself with a necromantic facsimile of life, you gain 1d4 + 4 temporary hit points for the duration.

Given the negligible cost in casting it (outside combat), wouldn't every warlock just keep casting it round after round until they got 8 temporary hp which would then last 1 hour? And then do it again when those expired. And again. And ...

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – mxyzplk
    Sep 8, 2017 at 12:22

3 Answers 3


Sure, it can't hurt.

Assuming that the player agrees (and I see no reason for them not to), yes, you can just assume that a warlock with that invocation starts with their buffs on.

I played a 3.5 game where all of us were using highly optimized, self-buffing characters who would stack buffs on ourselves before every combat. It was a waste of time for everyone to announce their buffs at every encounter, so the DM just assumed that we had them on at the start of each non-surprise encounter, and we subtracted the resources ourselves. We never had any issues with this system.

Just don't forget about it--having a spell constantly on like that means that they will show up on detect magic, for example, and there might be situations where constant obvious spellcasting might draw unwanted attention.


This is a topic that came up in our recent campaign.
We agreed that just like a person doesn't walk around repeatedly holding their breath in case they fall in water, a fighter doesn't walk around with his weapons drawn, my Warlock doesn't walk around expending the (even relatively little) effort to keep recasting a spell on herself 'just in case'. If nothing else, calling upon my pact over and over without any real reason is a draw on my patronage.
If on the other hand, we see combat coming, then I cast the spell as we ready (just as everyone is able to draw their weapons) and I roll 1d4+4 (once).
edit: For example, if we're walking into a magical tower where the Lich was last seen, I'm casting False Life. If we're strolling through the woods on 5hour march to our destination, I'm not recasting it regularly.

Why not always start with 8 hitpoints? Simple. I only know the spell worked. Not how well it worked. Whatever my first successful cast gives me, I have no reason to believe I can do it better by repeating the process.

Thanks to @IcyFire's comment. We play that PCs don't know the numbers of their stats. We know a clean, hard hit vs a glancing blow. We know when healing has made a substantial difference vs when it only seemed to stem the bleeding. So I acknowledge that this part is probably not relevant to all.

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – mxyzplk
    Sep 8, 2017 at 12:23
  • 1
    \$\begingroup\$ Comments are for suggesting improvements to the answer or for requesting clarification, not for extended conversation or argument. I've deleted the back-and-forth comments above. Further discussion should be taken to Role-playing Games Chat. \$\endgroup\$
    – V2Blast
    Oct 25, 2019 at 5:53
  • \$\begingroup\$ Knowing how the spell works, and how it's not always equally effective, the Warlock could still cast it for a minute or two (in other words roll 10 or 20 or more times), and take the highest. This also fits thematically... The Warlock "meditates" for a few minutes to maximize the amount of fiendish vigor they receive. \$\endgroup\$ Sep 8, 2021 at 7:54
  • \$\begingroup\$ "At will" also kind of indicates, that this is negligible effort for the Warlock (similar to, say, using the action for playing an instrument). Like a bard could go all day playing, a Warlock could go all day doing at-will invocations. Now nothing wrong with playing a more gritty game, but that's house rules to make the game harder than the RAW says. \$\endgroup\$ Sep 8, 2021 at 7:59
  • \$\begingroup\$ Key difference to eg. hiding is, with that the new roll will take effect if player tries to hide "better" even if roll is worse. But with temp hit points, the highest result so far will remain in effect. \$\endgroup\$ Sep 8, 2021 at 8:03

The Invocation "fiendish vigour" states You can cast False Life on yourself at will as a 1st-level spell, without expending a spell slot or material components.

So it wouldn't even take a turn (action/bonus action) you can literally cast it as many times as you want in one turn with no care for the action economy, you could practicaly say you just take 8 less damage from all sources.

  • 5
    \$\begingroup\$ That's an interesting interpretation; can you support it a bit more by showing how "at will" works in D&D 5e? I mention this because there is an entire section in the Monster Manual that discusses at will spells. I mention this because if you look at the text of the spell itself, it requires an action to cast. (See spell description in the PHB; Casting Time). Welcome to RPGSE. The tour, How to Ask and How to Answer show how to get the most out of this site. \$\endgroup\$ May 17, 2020 at 15:52
  • 2
    \$\begingroup\$ You may wish to look at the question "What does it mean to be able to cast a spell “at will”?" and its answers and see if you need to make an adjustment. Your interpretation and their doesn't quite match. \$\endgroup\$
    – Someone_Evil
    May 17, 2020 at 17:39
  • \$\begingroup\$ Welcome to RPG.SE! Take the tour if you haven't already, and check out the help center for more guidance. Your answer incorrectly interprets the phrase "at will"; see the question Someone_Evil linked above for more information. \$\endgroup\$
    – V2Blast
    May 18, 2020 at 2:32

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