With that build I can handle any damage and also can kill enemies easy ! First, you start with blue and after lvl 4 you are ready to do some gangs. With your high armor penetration and Defensive Ball Curl (W) you will do nice damage on enemies. And with that build of items you can easily tank in teamfights also do your job. For Example: in a teamfight you taunt their AD/AP carry with your activated W and Ultimate, you probably disable him/her for a long time or maybe can get the kill, also you can use your Raundin's activate for slowing enemy champs that provides your team to kill them easy. I just think thats a nice build/runes/masteries because when I do that I got a pretty nice attack damage and with my penetration runes I kill them easy.

(THAT POINT IS IMPORTANT) Note: If enemies got AP champions that are fed you can take Force Nature instead of Atma's Impaler and if they got fed AD's you can take a Thornmail instead of Atma's.

Thats All TY.