'white horned' = Nael van Darnus, the White Raven
'black horned' = Gaius van Baelsar, the Black Wolf

With that cleared-
Gaius is actually 100% against Meteor, he is very sure that Meteor itself is an error that will threaten the Garlean Empire as well and goes as far as straight out telling you to go kill Nael because that would be better for him and the Empire.