Non Armor Defenses

Non-Armor Defenses, or NADs, is a /tg/ term derived from a game mechanic in Dungeons & Dragons, which became a part of the game with the 3rd edition. (Previously, we had Saving Throws. See below.)

Back in Advanced Dungeons & Dragons, players had a wide array of class-based (and sometimes race-modified) saving throws they could make against different kinds of threats; these got kind of convoluted, with separate saving throws for both spells cast directly by a caster and for spells cast from a wand, for example. So, when third edition rolled into town, they discarded the extensive list and replaced it with three new defenses; a player just had to roll the appropriate save when it was called for.

Fortitude covers how tough a character is, and thus how well they can resist things like poison or disease.

Reflex covers their agility, and defines their basic chance of dodging a dragon's Breath Weapon or ducking into cover from a fireball.

Will covers their strength of will, which defines how easily they can resist mental attacks.

4th edition changed these by switching them from being a save the player made into static defenses, which is arguably where the name came from; now, Fort, Ref and and Will were player scores the DM had to roll against, like Armor Class, rather than saves the player had to make.

5th edition either expanded on or abandoned NADs entirely, depending on how you look at it, replacing the whole system with a universal "make a saving throw with a bonus/penalty from the relevant ability score" style mechanic.

Star Wars D20 Saga Edition, a spin-off (rules-wise) of a spinoff from D&D 3e, took the unusual step of removing Armor Class and rolling it into Reflex. This carries the oddity of armor making it easier to dodge things, but this matters less than one would think since only NPCs and specialist PCs wear armor in Saga Edition and most of the cases are situational anyways. (Unless you go balls-deep into armor specialization, in which case you become a hybrid of Batman and Ironman and more generally an unhittable, unkillable, do-it-all combat machine who bristles with 37 flavors of death.)

13th Age also has a more simplified variant, keeping AC while giving only two NADs with only Physical Defense (measured by the median of your phyiscal stats) and Mental Defense (measured by the median of your mental stats). However, while AC can be influenced by what armor you wear, your NADs are not so easily impacted.

Saving Throws

Before 3e, like a lot of things, we had a confusing mess. AD&D's system was known as "Saving Throw against X"; a character's saving throws were as follows:

• Paralyzation, Poison, or Death Magic
• Rod, Staff, or Wand
• Petrification or Polymorph
• Breath Weapon
• Spell

The first fun thing? This was all governed by a bigass table towards the back of the PHB (also found in the DMG), with no explanation of how it was derived, and had bonuses and penalties that you had to add and subtract yourself.

The second fun thing? Figuring out which saving throw to apply. During the 1st Edition, no explanation was offered, so nobody knew what save to use for a polymorph wand or paralyzing breath weapon. 2nd Edition had an explicit "top down" rule (higher on that list? Higher priority, with a few notable exceptions).

Fun fact: "Saving Throws" originated in Tony Bath's Rules for Medieval Wargames, where attackers made a to-hit roll, and then defenders had a "saving throw" to see if their armor protected them — as every unit in that game was a one-hit-point-wonder, this was the only way of surviving such a hit. Chainmail then chose to include saving throws for Hero units. To provide a bit of the feel of Chainmail's saving throws, the rule for dragon's breath was as follows: "Dragon fire will kill any opponent it touches, except another Dragon, Super Hero, or a Wizard, who is saved on a two dice roll of 7 or better."

Save or Die/Save or Suck

The problem

One common complaint in a lot of systems is that conditions tend to be rather fatal or completely debilitating, like blindness or losing all non-movement actions. This effects are typically known as "Save or Die", "Save or Lose", and/or "Save or Suck" in order of descending lethality/nastiness with no clear line of division (aside from spells that do cause outright death clearly being the first name). Among the systems this problem exists in are several editions of Dungeons & Dragons, Exalted, and Call of Cthulhu.

Ultimately, the issue isn't in saving throws themselves, but in the ease of obtaining effects that cause instant death or incapacitation and how they are no easier to make than effects that merely deal damage. Later D&D editions dance around this issue by putting these abilities, in the hands of NPCs, at high levels. It's why you don't see any mage NPCs in 5e slinging sleep spells, even though that is the god spell at low levels. In a PC's hands, it's overpowered and able to end encounters in a single cast, but nobody cares since the NPCs are NPCs; but if an NPC slept an entire party in one go… yeah, the PCs would be pissed (but only pissed off on NPC, not at GM; after all, NPC can cast same spells as PC's can).

That is generally the problem with Save or Suck spells. When players use them, they're great, but when an NPC uses them, they feel horrible. Either way, they're overpowered.

Differentiation

There's a rough attempt to make lines of division between "Save or Lose" and "Save or Suck". "Save or Lose" is when a character/unit is outright incapacitated, and can't do pretty much anything; e.g. paralyzed, unconscious, turned into potted plant or inanimate object, etc. "Save or Suck" is when a character/unit is "merely" severely hindered, and can still do "something", albeit badly; e.g. blinded, immobilized, deaf, mute, etc.

But then, there's some in-between examples that blur the line between "Save or Lose" and "Save or Suck" — e.g. magic sleep (gets interrupted by taking damage), charmed (gets interrupted if caster harms the charmed creature), magic fear (runs away from you, and has short duration), etc. And there's some that blur the line between "Save or Die" and "Save or Lose", if the victim is not technically killed, but is permanently locked into an "incapacitated and incapable of doing anything" state that he can't recover from by himself and that is relatively hard to recover from even with outside help; e.g. "turned into potted plant/inanimate object with permanency", "paralyzed with permanency", "put into magic sleep with permanency, what doesn't wear off even if taking damage or being subject of any mundane method of wakening". Or, generally, "Permanency" applied to any "Save or Lose" or "Save or Suck" can be really harmful.

The most horrendous variants of "Save or Lose" — making the target permanently, irreversibly incapacitated (or at least permanently incapacitated in a way that would most likely require going on an epic quest to reverse, such as the "imprisonment" spell) — are another thing blurring the line between "Save or Die" and "Save or Lose" (and can actually be worse than "Save or Die", especially if casting resurrection spells isn't something the victim's party finds to be difficult or cost-prohibitive; "Save or Suffer-Fate-Worse-Than-Death" perhaps?).

Yet another option what blurs the line, is the "baleful teleport" aka "very scary and confusing destination am i choosing!". Target gets teleported into place of spellcaster's choosing - under earth, on bottom of the sea, into air, into prison cell, into dungeon/labyrinth/tower/etc, into monster's stomach/innards, into specialized "killbox" designed to kill occupants with gunfire from all directions, into surface/core of the star/black hole, into another dimension/pane of existence, etc. Whether it's "Save or Suffer-Fate-Worse-Than-Death"/"Save or Die"/"Save or Loose"/"Save or Suck" depends on what the destination place is, how dangerous it is, and how hard it is to escape from it.

Yet another attempt to distinguish "Save or Lose" from "Save or Suck", is whether or not successful use of that ability would end the battle and give you Experience. If target is outright defeated, it's "Save or Lose"; if target is merely inconvenienced, it's "Save or Suck". E.G. being put to magical sleep/paralyzed/unconscious/turned into potted plant/petrified/teleported to other continent is "Save or Lose" (as enemy can't do anything to you, and would take quite a lot of time to recover without outside help); being slowed/blinded/deafened/muted is "Save or Suck" (as enemy can still try to harm you). Yet some cases still blur the line (teleportation elsewhere depends on how long it takes to return and how dangerous the arrival point is; easily-interrupted statuses like magic sleep and fear; some characters recover more easily than others).

TL;DR, E.G.: If the target dies on the spot — that's "Save or Die". If the target is turned into an inanimate object, completely paralyzed, or rendered unconscious — that's "Save or Lose". If the target is blinded, rendered incapable of casting spells, or turned into a tiny adorable critter — that's "Save or Suck".