Invisible penalties.

[Veknironth]

Well, this is a prickly one. What are the negatives/bonuses for someone attacking while invisible:simple? The spell doesn't give any. Invisible Haze, the Super psionic power, says attacks against an invisible foe are -6 to s/p/d. If you're blinded by Blinding Flash, you're -5 to strike ad -10 to p/d. A Cloud of Steam prevents you from opening your eyes and you're -9 to s/p/d. The same is true for magical Darkness (-9). The ward Invisible makes someone -9 to strike the invisible person/object. So, is it -9 to all since that's the mode?

Second, how much blood would you say gets on an invisible person who kills another? Certainly the weapon is going to be coated, but how much spray would hit the invisible attacker, and how much of an effect would that have on the nebulous negatives of invisibility?

-Vek
"Probably an answer in a Rifts book."

[Kraynic]

This is not by the book at all, but just for my own sanity, I have changed these so that fighting an invisible foe is always a -5 penalty and being blinded is always a -10 (unless you have abilities that might compensate somehow).

I don't think enough blood will "stick" to a blade to make much difference. Anything else would require you figuring out if there is arterial spray and whether it is actually spraying an area or being hampered by armor/clothing. By the time you get that all figured out all characters in your games will be stocked with small bags of flour...

[kiralon]

I thought to parry you had to be able to see the attack, eg can't parry attacks from behind.

[Soldier of Od]

We use the -6 to strike, parry and dodge from psionic invisibility for all invisibility, as it's the only one that gives numbers. I figure the penalties for fighting an invisible opponent are (and should be) less than those from blindness, because you can still use your sight (as well as other senses) to estimate the opponent's location based on other visible things such as terrain, other people or objects, and movement of flexible objects in the such as curtains, clothes, plants, etc. influenced by the passing of the invisible person.

Note that the -9 from the invisibility ward covers objects only, not people. I presume that is based on an assumption that objects don't (usually) move by themselves, making it harder to locate than a (usually mobile) person.

[ShadowLogan]

Well, this is a prickly one. What are the negatives/bonuses for someone attacking while invisible:simple? The spell doesn't give any. Invisible Haze, the Super psionic power, says attacks against an invisible foe are -6 to s/p/d. If you're blinded by Blinding Flash, you're -5 to strike ad -10 to p/d. A Cloud of Steam prevents you from opening your eyes and you're -9 to s/p/d. The same is true for magical Darkness (-9). The ward Invisible makes someone -9 to strike the invisible person/object. So, is it -9 to all since that's the mode?

Technically Invisible Haze doesn't make you invisible (pg175-PF2E because powers like "See the Invisible" and " See Aura" cannot counter it). It's a hypnotic suggestion that makes you think you are invisible. I'd be hesitant to use it as the basis for penalties in terms of real invisibility instead of a hypnotic suggestion that might use different penalties as the target's mind(s) still is aware of them on some level (so they can edit him/her out).

I'd go with -9 from the Ward. Interestingly enough the Turn Weapon Invisible Magic Weapon feature doesn't impart penalties, but rather invokes bonuses to strike/parry and initiative (pg249 PF2E) against those who cannot see the invisible, but this might come down to the fine tuning of what is invisible (part of instead of everything).

Second, how much blood would you say gets on an invisible person who kills another? Certainly the weapon is going to be coated, but how much spray would hit the invisible attacker, and how much of an effect would that have on the nebulous negatives of invisibility?

How much blood is likely going to come down to several factors like:
-the location of the wound(s), some locations are going to have bigger sprays
-the type of weapon
-what the target is wearing in the location of the wound(s) as the clothing/armor could block some portion of the spray of blood.
-surface area the psychic is presenting toward their victim
-distance separating them
-the size of the droplets and how far apart they spread.

For simplicity it is probably easier to just assume that unless you are w/n literal "hugging" range of each other (i.e., both w/n arms reach) you don't get enough blood on you to be much of an issue.

I don't think you'd really start to reduce penalties until like 50% coverage from a given angle, and even then, it's also going to come down to what got covered in blood (if you can only see the torso and not the limbs it would be easier to strike but not parry/dodge).

[Stone Gargoyle]

Since you cannot see the invisible character, the penalty to strike them would be the same as if you were blind, with less of a penalty if you take time to try to hear or smell them.

[The Dark Elf]

Since you cannot see the invisible character, the penalty to strike them would be the same as if you were blind, with less of a penalty if you take time to try to hear or smell them.

Disagree. As others mention, fighting something you cant see but can see everything else would be easier than fighting whilst blind to everything around you (and you'd be more cautious). Imagine if its raining or you're fighting in the snow or a swamp. Even if the foe is invisible you'd have a good chance to hit.

I think invisible -6, blind -9 is about right IMHO.