god of war :D

so if you played god of war when you attack AI , on AI will show sign on top of head when you press it it will play animation kill, so how it can be made? any tutorial, cheap asset?

 

When enemy life is low, play stun animation and disable all logic. Enable the "sign" (which is circle) above enemie's head. When character comes close to him and presses a button, initiate animation sequence where he kills enemy.

That's the whole logic right here. I would suggest you to learn basics. Basics would allow you to build complex games. So hit that "Learn" button on top!

PS. I am a fan of God of War

 

is any tutorial for that?

 

What elmar said.

 

Chances of finding such tutorial is nearly zero. Once again you need to learn basics first. With basics you'll be able to understand how Unity works. Then you should make some random projects. Then start over. Repeat until you are confident with programming.
And then finally, you'll be able to create such systems from scratch without any pre-made tutorials and little assistance.

If you're looking for a link then start here: http://unity3d.com/learn