I have a bad habbit of breaking rpg games, see bellow some absurd combos I've found and encountered:

*Agnea/Inventor - (Passives: bp, extra turn, full limit, X) on extra turn aoe akara's coil giving all hp/sp/ 3bp then rest of team can butcher everything on turn1

*Hikari/Arcanist - Aoe counter/dodge/full hp/sp sleep/ imortality seal.. ; Bonus with dancer divine buff can make whole party invinciple for 4 atks or aoe reflect

*Hikari/Arms master - accuracy build 4-8 hits on learned skills, can break all fast and dish out max dmg twice with axe skill

*Particio/Thief - turn1 max bp thief divine skill (with good setup 99999 dmg)

*Particio/Arcanist - aoe dodge/heal status cure/imortality seal -dish out consistent damage with hire aswell

*Throne/Dancer - dancer divine skill/2x turns/ theif max dmg divine skill/ cough cough EX buffs at night what more can you expect

*Temenos/Armaster - consistent 6 shield break a turn with limit charge, divine skill for 2x turns & support

*Castti/Inventor - max bp on extra turn - recharge limit turn 1, rinse repeat

Rest is abvious.

Seems getting merchant passives asap is the key to everything.