If you find him, you may find him destroying your house. If you come to close to him, you will find that your game will crash. If you do not come close to him, he will look on his map 5 minutes after you spawn into your world. Then he will chase you until he is in a 6 block radius of you, then your game crashes. If you escape, then he teleports to you and then it crashes. If you happen to escape still, then he will give up. The next time you go to bed, then you will wake up in the nether, and the chase repeats over again. If he never catches you, then your game will crash in 4 minecraft days after he first saw you. It all happened to me, so believe it.
Sometimes, you might find a tunnel with either a bunch of detector rails all over, or a sign. If there is a sign, the sign will usually say Death!@HEroBrinE or Die-death machine--hero-=brine. This is very rare, and if seen, you are extremely lucky... and very unfortunete. The best thing to do when you see him... if it is not to late arready, is to quit the game with no save, then click RESET NETHER in the options, and then go to creative/easy for safety. If he is not there, then you are safe. If he is still there, then repeat the process.
He will usually drop a few diamonds, string, and ender pearls, and sometimes a few signs and redstone torches. The only way to kill him that I know of is to use a stone sword and arrows. If you use a loot sword, he will try to take your sword and will attack. Don't use armor, because he will then know that you are for a fight. Find him, hide behind red glass pane, or lapuis laziliu ore. Shoot arrows until you hit. He will turn and freeze, due to the "person" that controls him being confused. He will look at the glass/ore and will stop, confused. Then come up, sprinting, and hit with sword. Remember that you must kill him before 4 minutes after spawning into the world. You will have an approx 50-50 chance to kill him, using the method shown. Please add any more efficent ways to kill him!!!