So erm i find out that 5th skill have atleast 3 skills for each character
still investigate but i think this is the best to K.O any boss
Team must have Cai Lin (Crystal Maiden model) and the one with Dagger (PA Model)
and this is 3 master will teach u skill for Cai Lin
Polar Master, Prietess of Ice Palace, and the last one is Mysterious Man in Nvwa World, near Water God
i try 3 skill and i believe that Mysterious Man teach u the best skill
He/She will teach u Nightmare that will make boss can't move, can't atk just like Bane do, but u can hit the boss and that Nightmare still deal dps.
the PA should learn 5th skill from Tiexue Man Leader that will help him have 2 passive that normal atk will cleave and Bash
after kill Injoker, CM should learn Shushan Heart from Head of Shushan, and PA should learn Ice Heart from The Lord of Ice Palace that will help him freeze boss when hit
Shushan Heart will reset cooldown all skill for CM, at lv4 only cooldown 20s
when fight big boss, keep Nightmare then Shushan Heart then Nightmare
keep that way and you will able to kill any boss xD
but ofc its depend on other boss give u good item or not :D
Sorry for my engrish :P