What traditional class(es) are you going to be?

[Cairdeas]

Assassin or Rounin.

You're welcome.

Yes obviously they wont call Great Katana's weapon class Great Katana in english, they didn't call any of the Weapon classes by their actual weapon name but a edited version of the name from latin. I don't know what Great Katana could be following their translation methods so far. So they might have to improvise.

I don't see it being Samurai. But Bushido is probably the best choice, As the Katana is Bushido's primary weapon of choice. If not Bushido then Parivir (Job name from Tactics Advanced 2 that was essentially a Samurai.)