So I’ve been doing this cleric c1> c2 > Krivis c1 > c2 > ??? > oracle > Kabbalist. I might go with Druid c1 instead of oracle, taking suggestions about that too. (Yes I know Oracle is mostly useless, but I really like these utility skills and I’m not really competitive about ranks or something. )
I was going to make Krivis c3 but read the forums and melstis seems like it’s very situational and mostly useless, what should I go with?
(I’m going full INT with a little bit of CON)
My Opinion: Krivis C3
That is what I’m going to build too. and Krivis C3 is good, Lv15 Zaibas, Lv10 Divine Smegma, More points for daino, Lv5 Melstis, it’s totally good compare to only 1 circle of Druid.
Just my 1cent though. 
I’ve just made some research and people say krivis is totally useless because people can get daino scrolls and other buffs are not that great, how true is this?
If you want to have oracle or druid at rank 6, pick either krivis3 or cleric3 at rank 5.
Krivis 3 doesn’t add much. It’s basically just for a better Zaibas. Melstis is too situational.
Cleric 3 will add some dps with more heal squares and cure lv 15, and also more heals, but you don’t need them that much being INT and cleric 2. Guardian Saint isn’t worth a single point.
I personally prefer cleric because when with a party in endgame, both zaibas and cure damage will be considered weak compared to wizards or archers skills. So cleric still gives you more heals. Krivis might be slightly better for soloing.