The best [[available]] Fire SSR's are Amaterasu and Svarog; you'll most likely end up using an A Frame Def Debuff as EX Skill , Thunder are Tyr and please don't run Thunder lol
Actually the main reason why I choose THUNDER was to cover up for FIRE's weakness against WATER, but I can still change my secondary to WIND since it's my 3rd strongest element if necessary.