The best end game combo teams are either kurama naruto, roshi, bee or edo hiruzen, shisui, asuma wb.

Both are viable as fire main, but they'll work better with earth main.

Fire main end game lineup would be itachi sasunoo, madara(founder), madara(five kage), shisui, masked man. They are all fire type ninja.

Thing is you can hardly put a team together for Scarlet Blaze pulling just from treasures, most of the best ninjas for that main specifically are "premium" meaning you have to use coupons, as a replacement for ingots, to get them. Those are Shisui, Anbu Itachi, Edo Hiruzen and so on. Unlike Lightning Main who can build actually end-game competitive teams pulling from treasures. You can try to get Danzo, Mei or Onoki from Kage Treasure or even go Susano Itachi but it's a long shot, in the end if you want to be fire main the best you can do is save your coupons to build a team (which isn't always smart if you're f2p since usually you want to use those in power).

Well a great f2p fire main team in my opinion is. Jinpachi, Kinkaku (3 stars atleast) fire main and danzo.

Skills : 14231

Summons: Demon fox and shiba

If u want to change it to be a bit more defensive i can run illusion mirroring instead of pheonix fire.

Front row has great shields and combo increase thanks to kinkaku. Team works actually pretty decent in arena too