There was a supplement called something to do with Beholders that talked a lot about their society, I don't have it to hand but it is doubtless somewhere at Uni.
I remember it saying essentially:
- Beholders show a great deal of differences as a race (size, pigmentation, shape etc).
- Beholders living together in hives tend to share very similar characteristics (the aforementioned size, pigmentation, shape etc).
- Each beholder believes itself to be the perfect representation of the Beholder ideal; I think this is something they are born with.
- Beholders consider all other races inferior to them and will tend to kill them or use them as slaves; and only rarely will they work with them. Note this applies to the illithid, kuo-toa and drow too.
- Beholders will attack and destroy beholders who are different from them (in size, shape etc...) pretty much on site, believing them vile mutants who taint the beholder race.
- Beholders will even kill their young as soon as they hatch if they appear too different from their parents.
- In short, each beholder sees itself as perfect and will kill or enslave anything it deems inferior.
I would concur with NiGHT that a beholder who did not fit in idealogically with other members of the hive would have to leave very quickly... Though I do not know what might happen if one was to be alone essentially since birth. Examples of loner beholders include the Xanathar... This is a creature working with some Thieves' Guild in the Forgotten Realms. A bunch of them serve the Church of Bane, too. Anyway, uh, I'd think that pretty much every Beholder in a hive is Evil, and most of the outcasts/loners are too.
Spectators are LN, yeh, I am not sure of their origins but will try and find out if it was indeed the Church of Helm. I do not think they associate with other Beholders, in any case despite ingame graphical representations they are meant to be a lot smaller and weaker than true Beholders.
I don't know how official Gauths are or if they live with true beholders.
Eyeballkin beholders are (I think) LE; note these are not part of mainstream Beholder society but are bred by Evil spellcasters as familiars.
Death Kiss beholders were (again, this is from memory) bred by the Phaerimm to fight Beholders. I dunno if they live in hives, but again, they're Evil.
Death Tyrant beholders are CE undead creatures and serve their creators (mostly the Church of Bane, I think).
(I am not really making a point about Virtue, just Beholder ecology)
To try and make a Virtue-related point: If the PC knows anything about Beholders, then I do not think killing them should incur a Virtue hit. Especially when they are hostile from the outset.