nightmare batmans core I will say it would be his passive i like to focus this build on the abilities of healing quickly meanwhile make tons of damage quickly and getting out of the Team Fight without you even noticing he killed you.



In the early phase I start with  the   Coda Blade (4)  Because it gives you a nice amount of ad and atack penetration after that i would say its absolutely CORE item its  [[Deathstroke's Claymore (2)]] to make damage by life percentage that will stack with your ultimate and you could make lots of damage  to any enemy champ 



in late game your job its to focus on the assasin or the adc to kill him  in the team fight with your ult  and then killing the others quickly 
  
 

startin with the Coda Blade (4) will give you a nice amount of damage and armor pentration 

[[Deathstroke's Claymore (2)]]  this will stack with your ultimate

[[Soultaker's Katana (4)]]