How to change Npc capacity?

Hi! I have a small persistent problem with an NPC that is supposed to attack AND go fast.(Oh, and also, it's supposed to One shoot the player when they hit it, and if that's possible (if that's too hard, don't include the question) the npc has to see the player from a distance, like if the player is far from the NPC, well he recognizes him and follows him anyway, even if he is about 1000 meters from the player. too hard to include everything in a script, you can remove the last request, it is not too important ;) Thanks for your time to help me!