When you use things like jutsus and your near several people, then it shows the pop-up that asks you who you want to use it on.[Homing jutsus] So to avoid this and makes battles faster/easier, there can be a focus verb that lets you focus on one opponent, thus only enabling you to hit him instead of others. Also, to avoid abuse, you can only use it on someone within your sight, and it wont lock-onto him if he is off-screen.
