I enjoyed the characters introduced by all the guests in Campaign Two and in general dislike picking favorites or ranking things, but if you pressed me, I'd have to say I absolutely adored Nila.
The character was like a breeze at a time where one was sorely needed, Sumalee brought in this fun serenity that really fit that particular moment in the campaign.
But really, the guests always bring their A game to the table, I liked all those characters.