The key to taking down the fire knight is multi-hit and TM control.  Get his Shield down quickly with multi hits or ally attacks and keep it down with TM control.  Geomancer, Artak, and Scyl should work fine for TM control and Damage, Kael, Rhonda using their Multi hits three hits.  Just make sure your AI is set up to start with those multi-hits to start the 3rd round.  Don't use Multi-hits on round 2 unless it's their A1.  Set up Geo to take his second turn for his A3.

Still cant pass it , i forgot to tell that its not needed to be on auto mode. If anyone have any other advice I'll be very glad to hear you.

you need Alure, she is perfect for this

deacon in lead, ruella, rhonda, artek, scyll.

i see a couple problems, you dont have these champions fully leveled or ascended. Also judging by arteks gear you are not equiping champions properly.

I've allways thinking that my gear is not good , can u tell me what gear to use , because ive been beaten in arena from teams that are 80-90k of power while mine is around 120 

Just judging from your Artak, you seem to have a problem with lacking speed...

Arena is mostly depending on the synergy of your team, coupled with speed.

So a Righteous set for Artak ?

forget the set.

100% crit rate
200+ accuracy
190+ speed

Thanks. Can u tell me other good gear for some of my other characters ? 

The general strategy for dungeon teams is to do one of the following:

1) Make the other team never be able to damage you, so you can ignore defensive stats, or

2) Have someone who can revive in case you do need to deal with damage

My suggestion is to go with the former. Something like Geomancer + Deacon + Seeker + Ronda + Scyl.

The key is for everyone to be fast. Damage is really not as important as speed. Make everyone have at least 200 speed, Scyl ideally closer to around 250. Geomancer and Scyl also need to have around 200 ACC. Have Scyl AI set to use A2 on opener + disabled for the first two waves, so that she has her stun ready for the start of each.

Here's my recommendation (And it's just that, a recommendation, not a criticism):

1) forget about sets for now, focus on the stats of the artifacts you are equiping.

2) recommend you put aside FK 13 until you can reliable farm Dragon 20 and get the 5 and 6 star gear from there.  Once you start farming Dragon 20, immediately sell any gloves and chestpieces with a flat stat for it's main stats, anything that does not have a speed substat, and any boots that don't have speed as a mainstat. Upgrade artifacts to level 8, if you doen't get at least one speed roll from that, sell it.  

3) My initial preference in general is: Gloves C.RATE%, Chestpiece either ACC or RES.

4) focus on the needs of the specific champ you are trying to gear.  If all you care about is keeping them alive, use HP% or DEF% gloves, RES Chestpiece, RES Banner, HP or DEF Amulet and ring.  If you want them to be a nuker, C.DMG gloves, ACC (ATK?) chestpiece with SPD and C.Rate substats

use coldheart and armiger, that is how I took down FK 13