League of Legends (LoL) Question: katarina or fiora

Katarina. Unless you love playing split-push duelists like Jax and Tryndamere, I don't think Fiora is really worth the effort for most players. Both champions have a moderate skill floor, but Kat is strong and feels amazing when you pull it off imo. Fiora is just kind of fun because her 1v1 is good and the mechanics are pretty smooth, but she's harder to be effective with, especially if your team's behind or you get counterpicked.

Can't guarantee which one you'd prefer, but I think you're more likely to like Kat.

Well.... Do you like bursty champion or extended fight champions? Do you prefer pure melee or would you like a little range? Do you want glass cannon or do you want some sustain. Do you prefer top lane or mid lane? Do you prefer dueling or do you want to pop in and assassinate someone?

kata is easier,stronger and more fun than fiora

IMO Katarina is easier to master (kind of biased as I main her). Kat has one of the highest burst damage in the game. If you'll be able to put time and effort into practicing her, then she is definitely the way to go especially if you look to climb. She is unstoppable when fed and can 1v5 easily. There are many YTers who provide decent gameplay/tutorials of Kat such as KatLife and KatEvolved.

No one said you can't play both of them. If your team needs a bit more tankiness, Fi would help. If the enemy team has a lot of people you can one shop with Kat, maybe she'll be a good idea. Plus Kat has ( from what I've seen) a fairly high ban rate, so learning more than one champ would help a lot.