Nah, a 5e Finger of Death only inflicts 7d8+30 necrotic damage because they wanted to remove most of the instant death effects from the game. It doesnāt even bypass the usual rules for what happens at zero HP, so if you donāt follow up by hitting them again they can be stabilized by anybody with a spare action in the next few rounds, and have about a 60% chance of getting back up on their own even if you leave them unattended.
Also 5e just calls it a Constitution Save, not Fortitude. This is probably from .0 or 3.5, in which that quick 7th level spell willĀ instantly kill anybody who isnāt prepared for it, but thereās a big pile of easy ways to become immune to the effect, at least temporarily, so by the time you can cast the spell anybody whoās tough enough to challenge you at all can probably render the spell useless. (and I think one of the basic traits of divine creatures in that system was no longer automatically failing anything on a 1, so you would need to pump your save DC higher than their divine Fortitude bonus even if they didnāt have any chance to prepare).
Save-or-die effects are generally too easy to negate to be used in a serious fight, at least with an intelligent opponent. Theyāre a great way for a villain to show off how powerful they are by bullying peasants, and they sometimes let you bypass monsters that are big and tough but unintelligent and nonmagical, but if you want to make them practical in a real confrontation you need to have some exotic trick specifically designed to negate the usual protections.
Or be up against a boss from an official published module professionally written by an idiot.
