Castiel is particularly interested in Esoteria so I would love to throw him into this adventure~ He has grudges against several people, though most aren't that serious. His moral compass is generally 'good' but he's an angel, so while he tries to go with human 'good' he ends up falling into angel 'good' sometimes. His morality is also very fluid and changes depending on situation and who he's with, so he should be in opposition to at least some people easy enough.