D&D 5E Why does Invisibility work against undead?

[Fanaelialae]

As a result of this thread, something I'd like to explore further is the idea that the senses of undead are generally based on those senses they possessed in life because that is what they are most familiar with. Perhaps undead gurus exist who have learned to harness their spiritual senses and no longer rely on the feeble senses of their previous existence. I think that there might be some cool story opportunities that might be had from that.

 

[Warmaster Horus]

Because invisibility is magic.

 

[jaelis]

Turns out skeletons just have invisible eyes!

 

[MNblockhead]

Undead have necromagically gifted sight. Invisibility magically hides you from the sense of sight.

It might be fun to have invisibility only work with mundane, physical sight. If you do go this route, I disagree with the poster above who said you need to let your players know. But you may want to let your players know that you you may deviate from many standard monster stats and abilities and that they should be careful about making assumptions based on prior player experience.

Part of the fun of the game is not knowing what you are getting yourself into when you encounter monsters and having learn through trial, error, and research.

 

[ppaladin123]

You could have levels of invisibility depending on spell slot level:

sight only
also masks sound
also masks heat signature
Also masks ground vibrations and changes in air turbulence caused by physical object (whisker-sense!)
Also masks thoughts
Also masks life force or necromantic force.

Get rid of improved invisibility (and perhaps some of the non-detection spells) and make what it masks dependent on the spell slot you use.

 

[Sword of Spirit]

One thing that my consistency sensor has issues with is the (apparently based on some AD&D material) idea that undead saw lifeforce or some such. That's fine if that is in addition to normal sight. But if it is their sole form of vision they are going to have a heck of a time navigating around dungeons, buildings, boulders, cliffs, etc.

 

[CapnZapp]

RAW are pretty clear and simple for vision in 5E. I didn't like that because I found that the different types of vision from prior editions added a lot to the game. Accordingly, for my campaign world, I introduced a lot more types of vision and vision approximating senses:

* Normal
* Low Light (ability to see clearly in dim light, extends radius of dim light)
* Darkvision (you produce a dim light that only you can see - limited range)
* Watersight (ability to see clearly in liquids - no range limit)
* Infravsion (see heat signatures - no range limit)
* Ultravision (see light in ultraviolet span - used to hide secret arcane writings, primarily - no range limit)
* Sonar (see with sound - beats illusions - limited range)
* Blindsight (like sonar, but doesn't require sound - beats illusions - limited range)
* Tremorsense (sense non-static things that touch surfaces you contact - beats illusions - limited range)
* Life Sense (ability to see souls - beats some illusions - souls radiate light like a lightsource, so it allows creatures with this sense to see you when you hide as easily as if you had a torch - no range limit)
* Devil Sight (see in any darkness as if it were bright light - some unlimited range, others limited)
* X-ray (see through most substances and concealment - beats illusions - limited range)
* Limited True Sight (Combines Low Light, Darkvision, Infravision, Ultravision and Blindsight)
* True Sight (all of the above - very rare)

I have a 5 page document that gives detailed rules on the above. If I ever get around to making it pretty, it will go up on the DM Guild. I also have a few races with unique types of vision, such as the illithid ability to see psionic energy as if it were a light source.

In my game, all undead have Normal Vision and Life Sense. Mere skeletons can see you coming before you turn the corner as your soul burns brightly for them - as if you were carrying a torch. Some undead have other advanced forms of sight as well, but adding this detail to undead gives them a creepy aspect that helps really differentiate a skeleton from a goblin. Hiding from undead is hard with life sense in play (but not impossible).

The other vision forms also differentiate other monsters. Orcs and other wilderness hunter races tend to have infravision rather than darkvision in my games. This allows them to spot prey at night from great distances. Underdark races tend to have darkvision, which is more useful for seeing within the confines of the caverns they inhabit.

You have to stop yourself and really consider the types of sight monsters and PCs have before encounters when you have this many vision types, but once you get used to it, it adds a lot of depth. However, until you get used to it, it can be a burden.

I am miffed they oversimplified vision to the extent nightvision was removed. It just doesn't work. Darkvision is a poor substitute. Also, it becomes too easy to create an all-Darkvision party which lets the heroes ditch all lights.

I really wished they would have retained low light vision for forest races like Elfs and Gnomes (and Half-Elfs).

You can still create a no-light Darkvision party, but you must depart significantly from the classic Human, Elf, Dwarf, Halfling party to do it.

It's no longer sufficient to go Half-Elf, Elf, Dwarf, Gnome to do it.

Sent from my C6603 using EN World mobile app

 

[Li Shenron]

The title question comes from my musings about HOW undead see the world. It just seems like certain undead, like skeletons, would not use our kind of vision. Therefore, invisibility would not work against those creatures.

Undead in my campaign have vision just like ours, but I am toying with changing that for my next campaign.

Thoughts?

I think you'll be fine if you change how they works, either all undead or some of them.

There is no special reason why undead should see invisible creatures, and there is no special reason why undead shouldn't see invisible creatures, so either way would work in a fantasy setting.

 

[Ath'kethin]

I think the OP's question leads to an even more fundamental one: how are skeletons up and walking around anyway? That's impossible!

I actually see the "undead vision" is situation as being analogous to how back in 2nd Edition, a high Intelligence score gave you immunity to illusions. Even though the text clearly stated that the game affect of this ability was automatically making your save against an illusion, people argued endlessly that a character with a high enough Intelligence could see invisible creatures (since invisibility is an illusion spell).

Hmm. Now that I write it out, it doesn't seem that similar after all. Except maybe in the "sure to generate heated discussion at the table" vein.

 

[Fanaelialae]

I am miffed they oversimplified vision to the extent nightvision was removed. It just doesn't work. Darkvision is a poor substitute. Also, it becomes too easy to create an all-Darkvision party which lets the heroes ditch all lights.

I really wished they would have retained low light vision for forest races like Elfs and Gnomes (and Half-Elfs).

You can still create a no-light Darkvision party, but you must depart significantly from the classic Human, Elf, Dwarf, Halfling party to do it.

It's no longer sufficient to go Half-Elf, Elf, Dwarf, Gnome to do it.

Sent from my C6603 using EN World mobile app

I actually like the simplification.

Previously, it was a pain to track who could see what in a party that included regular vision, low light vision, and darkvision. To the point where we ignored the lighting rules 95% of the time. (Obviously that might have been different with an automated VTT, but we were playing on a physical grid.)

In 5e, IME, even an all darkvision party will want light for a dungeon delve because darkvision penalizes your perception in total darkness. Obviously, in an all darkvision party, the ability to extinguish all light sources and sneak about is very useful, but for general exploration the disadvantage on perception checks means that you will set off traps that you would have avoided, overlook hidden treasures that you might otherwise have found, and walk into ambushes that you could have detected. My players certainly aren't eager to take such risks.

As such, I have found that (the majority of the time) a darkvision party has the same modus operandi as a non-darkvision party.