To add on to @mxyzplk's answer (particularly part 2):
Be Descriptive
You have to remember that (depending on the group/player, of course) a lot of what brings a character's personality out is their dialogue; if your character is shy and you're focusing on the 'quiet-shy' angle of that, you need to make sure that you're bringing out a similar amount of personality through descriptions of your actions instead.
A shy character isn't a blank mask standing alongside the party and is still going to have reactions to things going on around them, even if it isn't spoken aloud in character- describing how your character physically/emotionally reacts is going to be key to still feeling like you're present at a scene (both to yourself and to the other players/the GM) and letting everyone else continue to interact with you.
Basically, make sure the shyness stays as part of the character, and don't let it extend to yourself at the table.
Another important point to remember is that 'shy' is different from 'mute'; There are still going to be times when you have to/are motivated enough to talk to someone. Remember to keep your character's shy personality in mind even in these situations, when appropriate. As a few examples, though hardly the only way(s) it could be approached:
- Make sure you describe yourself as being something along the lines of noticeably hesitant/nervous when approaching a conversation your character wouldn't be comfortable with.
- Intersperse occasional extra nervous phrases/pauses throughout your speech ('Um's, occasionally getting a sentence tangled up in nervousness, etc.).
- Side note: I like the idea you provided of the character coming out of their shell when doing something they're confident with. Something like this will help make the contrast between those times and the normal, more shy discussions more noticeable. You could even use this to effect in normal conversations if you think your character's getting less nervous with whoever they're talking with as the conversation goes on.
- Their reactions to social conflict may be different compared to the more outgoing people around them; Wincing when someone suddenly gets angry rather than trying to diffuse a situation/getting angry back, trying to quietly convince the party to avoid or leave a difficult social situation entirely, trying to end a social situation as quickly as possible if they're the focus, etc.
Also worth noting is to make sure that the shyness doesn't overextend itself into parts of your character that it shouldn't apply to- if they're only shy, and not just generally nervous/anxious about things, it shouldn't come through nearly as much in a non-social situation. A shy character can still be bold and take action.
First, you're off the hook for "My Guy" syndrome - this is clearly a conflict the GM orchestrated. "My Guy" happens when a player decides to use his character to justify derailing the plot, but telling you that your lost love is working with the enemy means that this is the plot. You're being presented with a genuine challenge that hinges on your buy-in of this conflict, and I'm willing to bet this was exactly how the GM hoped things would play out.
Second, you need to start looking for the shades of grey between "slaughter the cultists" and "join the Abominations". She's worth a lot more as an ally than as a corpse, and having her working as a double-agent or informant will give your group a better chance of stopping the cult for good. Taking her out prematurely removes your best source of information, and you might never get the access you need from anyone else.
Furthermore, you said she wants out of the Cult, which means Redemption is a possibility. If the Inquisitor can't find mercy, compassion, or hope enough to treat her as anything other than an enemy (in which case, they should probably be Lawful Neutral) convince them that she deserves something other than summary execution. Take her into custody, let her face justice and shine the light of truth on the whole cult. As soon as we move from "shoot her on sight" to "demand her surrender", then we buy time to redeem her.
You should also look closely at that "really only there to help a friend" angle. If you can rescue this friend, or otherwise get them out of trouble, then the cult loses its leverage over her. At that point her motivations will become much more clear, and she should be able to become a reliable ally.
Of course, betrayal is always a possibility, but you're usually better off trusting and getting burned in an exciting plot twist rather than shutting down the story early to avoid the risk. Optimism is more fun.
Best Answer
Differences that arise from different ways of perceiving and interacting with their environment are the easiest things to draw on for alien mindsets. (Harder are psychological, history-influenced sociological differences.) In this case you have an easy point of differences: they have no eyes, and sense their environment entirely via the Force.
Consider what we do with sight. We perceive:
So the question is, what are the primary things that someone senses who senses mainly via the Force?
So the main things that they perceive are:
Secondary things that I might extrapolate are:
What does that indicate about their view of the world?
It's a very people-centric view. Their dialogue would be almost entirely about the doings, motives, and feelings of people, those being the upper-most part of their experience of reality.
In some ways there's very little hidden to them, except by distance. Most of our metaphors about unknowns relate to darkness. For them, unknowns would be expressed through metaphors about being too far away or being unnaturally cloaked from Force sense.
They can't perceive colour or brightness. They wouldn't be able to operate graphical interfaces, except maybe by exerting their Force sight to grasp the workings behind the screen and trusting the Force to guide their fingers to do the "right" thing. They might be OK with holograms, since arguably there's some "presence" or "echo of the person" to a hologram, not just light. Their culture probably seems really low-tech to an outsider since there would be no obvious, recognisable computer terminals. Their technology interfaces are likely hard to understand for others – they can see inside things, so they're more likely to put device feedback somewhere inside it, where the stuff is happening, than than bother to displaying feedback on the surface. Buttons don't even need to look like buttons, because the difference between a surface that's connected to doing something and a surface that's just immobile casing is obvious to them.
Their social interactions are probably much more like mind reading, since emotions are so obvious to the Force-sensitive. They wouldn't say, "you look angry, what's wrong?", but rather "I feel your anger, and I see that it's misdirected. You are angry with yourself," or something like. They're probably kind of intrusive with other aliens, at least until they learn aliens' sense of tact.
They can see through walls. There's no ducking behind a wall to avoid notice, there's no way for people in the same home to have privacy without deliberately "turning away" and thus acknowleging the thing you're not supposed to see. They're probably not shameful about anything at all, what with all the feelings around them being obvious, and being able to sense the bright emotional beacon of your roommates "gettin' it on". Either that, or they're especially rigid about etiquette, with lots of social standards around what is and isn't seen. As a real-world historical reference, the sociology of Japanese paper-walled houses could be informative. (I can't find a link at the moment, though…)
They can't see where others are looking. There's probably a bit extra verbiage devoted to indicating what one is attending to in normal dialogue, simply because there's no way for others to tell what your senses are focused on and infer the context of words from that.
They can probably sense things that are invisible to light-seeing people. Things like invisible poisonous gas are probably spatially evident just like everything else. Ditto, they'd be able to tell when a space is in vacuum or has air in it. Maybe they'd even be able to sense air pressure.
They can't see a long way, unless they're very strong. (Think, "I haven't sensed that presence in a very long time.") Even then, they can't see forever. Their senses depend on how far they can extend from themselves, while light-seeing beings depend on how strong the light is. So, they can't see stars, except maybe as a very distant huge mass of existence way out there. A nice view is lost on them.
What does art look like when you don't look at art? Their plays are probably incredibly sophisticated, and lost on anyone who can't sense emotions. They probably sing. They're probably very good – potentially – at controlling their emotions, since it's an effective communication medium. They're probably as good at it as we are with body language – that is, most humans suck at "speaking" body language deliberately except for the most broad statements (like, "I don't like you"), while some few people can become very adept at controlling what their body language expresses.
Build some stock phrases or metaphors out of this. Have in mind how they'd talk about unexpected events, like an assassin intent on a killing sneaking into a dark apartment – they're going to perceive that very differently than their light-dependent companions. Build up a few scenarios in your mind that highlight these differences in worldview, and which are likely sorts of things to happen in a roleplaying game, and you'll have a lot of pieces from which to improvise during play.