•Build•
1.Str=280-300
2.Agi=ASPD 195
3.Dex= I'm not sure in dex... I think you need 450-500 hit? or 400 hit enough.
4.Vit= After you put stats in str,agi,dex the rest stats put it in Vit.
•Cards•
Hmm if i were you i go Sonic blow when i have Thanatos card but it's okay just use incantation.
Weapon Card=Inca,Skel,2xTG or Thana/3xTG
Helm=3xKiel/Fsold or Maya P
Armor=Tao,GR/2xTAO/2xOL= when dealing with champ using this so if he accidentaly asura you then he'll die with you too.
Cloak=2xRay/2xSkoll/2xDevs
Boots=2xFBH
Shield=Hmm i think just carry a shield with GTB for Magic Users.Shield with Usako card is kinda useless because you're using a Katar.
•Tips•
1.Always use Cloak. Remember you're an assassin. Assassin doesn't expose themselves [except if they're using maya P] so always cloak.
2.Bring a Cspeed so you can walk very fast and don't forget to bring EDP potion for EDP skill.
3.Use a linker to increase damage for SB.
4.Use backslide when you fail to kill an enemy or while someone is with sight/ruwach and chasing you fast. [be careful in using backslide you might get cornered or stuck when you spam backslide. Use it wisely.]
5.[For thana users] If you're using a thana and SB an enemy and your damage is kinda low [1k-3 each SB] use backslide then cloak then switch into other weapon [inca,skel,2xtg].
6.Remember you don't have shield so be very careful when pvping a champ you might get 1 hit. [use 2xOL when facing a champ so if he asura you he'll die with you too]
7.Hmm i'm not sure how many SB spams you can do [i think you can 3x SB simultaneously] just use backslide after you SB your enemy when you fail on killing it then cloak.
8.If the enemy is using 2x OL too use the Hiding Skill and Grimtooth him.
9.SB types are one of the fastest killers and the most fastest to be KO so be very fast on killing an enemy.
10. Enjoy.
I hope this simple guide of mine helps.