I'm making a Pantoran PC, who I plan to have disguise themselves before preforming any illicit activity. The disguise would simply be wearing contacts to give them fully red eyes. They wouldn't actively trying to convince anyone that they are actually Chiss, just attempting to use the natural habit of remembering things that are different to their advantage. Basically they are relying on any witnesses to describe the perpetrator as having "blue skin and red eyes" which would lead investigators to focus on finding a Chiss rather than a Pantoran.

How would you handle this as a GM?

I can think of a couple of ways I'd do it, depending.

First, the normal "disguise" skill is Skulduggery, so you could have a the player make a Skulduggery check. This is the simple way - if the character succeeds, the people left behind on the scene don't recognize them as a "pantoran with red eyes," they recognize them as a "humanoid with blue skin and red eyes," or possibly even "a chiss."

Alternatively, if the character making a check doesn't fit right with you, you could make a Knowledge (Xenology) check or a Perception check for the bystanders to see if they can make the same distinction. If the bystanders succeed, they recognize the species as Pantoran, despite the red eyes. If not, they either can't recognize the species and just describe, or mis-identify it.

One thing I would note, however, is that (supposedly), pantorans are fairly common, while chiss are fairly rare. So to the common folk, "pantoran with red eyes" will probably be the most likely default to seeing this person. Assuming that the bystander even sees their eyes, and doesn't just see the skin. Also, I believe that pantorans have white-ish hair, while chiss have darker hair - the character may need to dye their hair as well, as part of this disguise.

I personally would go with the Skulduggery check, probably with some setbacks due to some inherent difficulty in this deception, but that's me .

I'm making a Pantoran PC, who I plan to have disguise themselves before preforming any illicit activity. The disguise would simply be wearing contacts to give them fully red eyes. They wouldn't actively trying to convince anyone that they are actually Chiss, just attempting to use the natural habit of remembering things that are different to their advantage. Basically they are relying on any witnesses to describe the perpetrator as having "blue skin and red eyes" which would lead investigators to focus on finding a Chiss rather than a Pantoran.

How would you handle this as a GM?

I'd add a setback or two to anyone trying to identify your character based solely on an eyewitness description.

Edit: This is assuming the eyewitness didn't succeed on the roll to correctly identify your species, also with a setback or two.

Just to throw more considerations for the check structure into the mix:

Skullduggery check:

1. Average difficulty to change/conceal general appearance.

2. Hard difficulty to change sex (if a dimorphic species)

3. Daunting difficulty to change/conceal Species.

Upgrade the difficulty for each aspect of disguise they want to combine (appearance, sex, species) starting with the highest base difficulty.

Hand out Boosts and Setbacks as appropriate for pre-existing similarities/differences to the species (for example changing a Wookie - or anything for that matter - to look like an Ithorian is gonna have a lot of Setbacks).

If check is successful, casual observers/witnesses report witnessing as disguised. Someone scrutinizing the disguise closely receives a Vigilance check to see through it, at the appropriate opposed roll for the disguise skill. Possible Setbacks to see thru it if there was a Triumph while putting it together or something.

Just depends how mechanics heavy you wanna go.

I'm making a Pantoran PC, who I plan to have disguise themselves before preforming any illicit activity. The disguise would simply be wearing contacts to give them fully red eyes. They wouldn't actively trying to convince anyone that they are actually Chiss, just attempting to use the natural habit of remembering things that are different to their advantage. Basically they are relying on any witnesses to describe the perpetrator as having "blue skin and red eyes" which would lead investigators to focus on finding a Chiss rather than a Pantoran.

How would you handle this as a GM?

I like that you are role playing the disguise and how it fits with your PC, you'd be surprised how many times Players just say "we disguise ourselves..."

Anyway regardless of what your final disguise is the mechanic is the same and what you are describing is using The Right Tools for the Job (pg 181 F&D). Your PC would need to acquire a Disguise Kit (pg 187), or at least part of one and your GM may give you a discount if all you want are contacts. Your GM would then give you a Boost to your roll depending on the situation as the contacts may be fine for a casual observation but do nothing for a gene or optical scan.

I'm not sure why you wouldn't go for contacts, hair dye, and skin dye to adopt the appearance of a human if your goal is to be as inconspicuous as possible.

There is also a talent for it indistinguishable

Upgrades the check to identify the character for each rank of the talent you have.

There are also at least two "armor" that would also help.

Bland Clothing and Concealing robes.

First of all, your character is either assuming he or that general law enforcement knows what a Chiss looks like, those guys are pretty secretive and the only chiss usually seen out in the galaxy are the exiles so depending on the table I can see this idea being vetoed. So I would probably only give a boost dice for contact lenses/setback on recalling and alone I would probably say that just contact lenses isn't going to put off a sector ranger chasing after a heist mastermind.

However the concept of a guy who transforms himself before every job? Thats just awesome. Don't just stop at chiss, try having prospectics for being a zavarack, human, twilick e.c.t

There is also a talent for it indistinguishable

Upgrades the check to identify the character for each rank of the talent you have.

There are also at least two "armor" that would also help.

Bland Clothing and Concealing robes.

To be pedantic, it’s actually “Banal Apparel” [DA:47], but otherwise the above is correct.

EDIT: Also note the “Holographic Costume” [DA:48].

However the concept of a guy who transforms himself before every job? Thats just awesome. Don't just stop at chiss, try having prospectics for being a zavarack, human, twilick e.c.t

So, basically a Clawdite?

However the concept of a guy who transforms himself before every job? Thats just awesome. Don't just stop at chiss, try having prospectics for being a zavarack, human, twilick e.c.t

Yep this is a good PC concept and a Disguise kit will will give you all the necessary stuff to pull it off. Tool Kit's in this game are not just your average stuff they represent cinematic level items so think Mission Impossible. Remember though that a Tool is only as good as it's user so if you are going to go this route you can't expect the kit to do all the work. The kit is only going to help your Deception so you'll need to get a few Ranks and the Talents to enhance it and a Rank or two in the appropriate Knowledge in case you are questioned. Passing as a Chiss physically can be undermined if you can't answer simple questions about Chiss culture...

Have fun

I'm fairly certain that the RAW already has rules for this, but if you were to ask me to come up with a ruling on what I would consider a "passive" disguise to represent, it would be habitually altering your attire, appearance etc in (relatively) minor ways to force any non-invasive attempts to ID you to be opposed by your skulduggery. I wouldn't generally permit this sort of passive obfuscation to hide your true sex, species, etc, though tools and talents may provide a workaround for that also.