Is there an RP guild?
 

I find I enjoy the game more with some light RP.

I believe Auld Lang Syne is?

No, they are a non twinkage progression guild that does not use the Tunnel and earns their gear. Cool, but not RP.

SAO, CSA, SOTS , BHP , and a few others.

Not sure SAO is around anymore. CSA is way too small, the only one who RPs is probably me right now. SOTS doesn't really RP. Not sure about BHP.

Auld Lang Syne does have some RPers, or at least people who will play along if you start RPing. Second Sons seems to be advertising themselves as an RP guild (...although apparently a good portion of them are doing GoT themed stuff...?). Generally RPers are scattered amongst guilds.