GM is thinking about running a mini campaign centered in a nation that persecutes casters of and users of magic of any type. (Armageddon type magic war, yada, yada... )
So most of the party will probably be martial and/or scout types.
I want to make a caster that isn't obviously a caster. Still Spell, Silent Spell, Eschew Materials, and slight of hand skill are clearly desired. Spells or SLA's that don't have obvious visible or auditory effects will be best. I wouldn't think things like owl's wisdom, cat's grace, guidance, bless, or any of the detect spells would be noticeable. Any other good choices?
He would have to be at least good enough at a something to have a reason to be with the group. So able to fight, sneak, face, or other skills at least halfway decent.
How would you build this?
Play a psychic caster with deceptive and conceal spell/improved conceal spell feats. With the lack of verbal, somatic and material components you only have to focus on having full ranks in bluff to avoid being spotted.
Mesmerist is a good way to go with this. They have the skills to party with the rogues and have a very good spell list geared towards buffing the party and debilitating the enemy.
Psychic bloodline sorcerer also has potential with a better spell list and full caster ststus, but lack the skills to keep up with the scouts of the party.
The psychic class could also work, and with a high intelligence had the potential to have the skills necessary. Probably a stronger choice than psychic bloodline sorc.
You want your primary casting stat to be at least 18, after racial adjustments. Int for psychics or cha for sorc/mesmer. Kitsune, human, half-orc/elf, elf(psychic), gnome(sorc/mesmer) all make good choices for races.
Because you're looking for spells that don't have obvious visual effects (a person is going to know something is up if they swing a sword at you and your shield spell blocks it), your secondary stat is going to be con, ideally at a 16 and dex at a 14. You will be focusing on the save or suck spells rather than blasts. Fireball has a pretty clear point of origin as you evoke the bead and it goes flying from your direction. Make sure you work with your party so you avoid being the target of a full attack.
Due to the Spellcraft FAQ, all casters are spottable.
Your best bet are the vigilante for their hidden identity, and the feats that obscure casting. However, I hear the feats aren't that good. As for still spell and silent spell, they are good for bypassing requirements, but they don't affect the perception used for spellcraft.
If you really want to hide your casting you play a psychic caster and take Cunning Caster, not Conceal Spell.
Cunning Caster is a Bluff check vs their Perception, with penalties on the Bluff check for visual/somatic components. Since psychic casters don't have either of those, its just a straight Bluff vs Perception.
Plus it doesn't double the casting time like Conceal Spell does, and theres no Perception bonus for the other people based on the spell level.