The Khezu is powerful, but slow. It likes to wander in areas: 8, 7, 6 and occasionally 3 & 1. The best way to defeat Khezu is to use the old fashioned "Hit n' run" trick. This means, you should not jump in and continuously attack Khezu, otherwise he will crush you. If you briefly attack him while he isn't in his "Electric Shield", you could wipe the floor with him. I find the easiest way to take this guy down is circle him a bit and when he tries to shoot his lighting ball at you attack his legs very briefly and then dodge out of the way because he will almost always to a short ranged attack that is easy to dodge. Why attack his legs you ask Well, as he is attacking there is a good chance that you will knock him over and its an easy way do deal out some massive damage or put down some bombs. When you attack his legs make sure you don't get underneath his body because he will immediately trap you down there and then use the move "Electric Shield" which hurts a lot if you have armor with bad lightning resistance. Other than that don't try and use flash bombs on him because it doesn't have eyes and good luck! Dung bombs will not stun it, but it will pause for a second and lose your scent in the nice big, brown cloud of Popo excretion (You're welcome for that wonderful mental picture). This gives you time to flee or dish out a fewwhacks. Here are some guides about Khezu behavior: (see Khezu Behavior section)
If Khezu lowers it's head while giving a grunt/roar, then it is most likely to use Body slam attack. This is it's 2nd most powerful attack, so beware. It can be blocked, but it could be dodged all the same. I believe it is best to dodge left or right. Or, you could run away when the khezu warns you with it's signal.
Volt Tackle/Electric Body Slam
Khezu gathers electricity and jumps forward, he only does this in rage and this is a sign that he's almost finished, it is easily dodged if u attack him at the sides .When he turns around to jump at ya just roll or jump outta his way!
The Khezu becomes surrounded by volts of electricity, and drops to the floor. This isn't very powerful, but you should still be careful. This is quite annoying, because, not only if you are using a combo attack on Khezu, you cannot get out of the way, but this makes it difficult for Blademasters to attack it. If it starts to energize in mid-combo your only hope in to start mashing the roll-dodge button while holding the backwards movement. Hunting Horn can be used to do a downward slam on the Khezu's head from a safe range. It can be guarded easily, and can also be dodged. Whichever method is up to you.
P.S. If you can pentrate it, the tail is a safe place to hit, as long as you aren't hugging it, if you are the static aura will hit hit you (A.K.A Dual swords not recomended for this technique :P)
The Khezu lowers it's head again, but this time, it jumps to the ceiling! This is not very common for the Khezu as you should be fighting him outside. This gives Khezu the opportunity to do two things:
A) Acid spit The Khezu will lower itself, hanging to the ceiling only by the foot. Then, it spits four drops of acid. That will make for super little damage, but can cause dizzy. After that the Khezu will drop at you. But, word of advice, never linger in the same spot while the Khezu is on the ceiling. Because, it likes pinpoint your location, then attack. B) Fall The Khezu will fall from the ceiling, and flatten you if you are standing on it's shadow. The Khezu will occasionally drop down even if you are not near. So, in conclusion, just watch out for Khezu's shadow.
The Khezu will extend it's neck and unleash a bite. This attack isn't hard to evade, but watch out for it. It can deliver quite a hit. Try Dodging, Sprinting or EVEN jogging out of the way!
If you are attacking the Khezu's legs, occasionally, it will bite wherever you are. It isn't very powerful, and just like the other attacks, can easily be dodged. The Khezu always bites to its left side
The Khezu turns around in a 180 degree turn. Perhaps the most annoying attack, considering it is difficult to dodge due to the speed of the attack. It is possible to dodge it by roll-dodging, but timing is difficult.
This is Khezu's most deadly attack. The Khezu gathers electricity in it's mouth and fires a bolt of electricity. If you notice electricity coming out of its mouth it will fire off three bolts, if you notice a high pitched sound (G-Rank Khezu only) and electricity foaming it will fire five bolts which cover the entire area in front of it. The best place to be during this attack is at its side or the side of its head attacking the head.
The Khezu yells a scream so loud, it stops you in your tracks, giving it enough time to attack you. This is the Khezu's most annoying attack. You can never predict when the Khezu would do this, and it isn't easy to run out of the way. Fortunately, the Khezu's next attack will be slow enough for you to avoid it.......hopefully. '
When you have significantly weakened a Khezu, The Khezu will puff and pant, and blue steam will emit from it's mouth. This means you have now angered it, and it will attack you with TWICE the speed! Now, it's attacks will be harder to avoid, so a couple of strong attacks can finish it, and it will snap out of it in time. It is a good idea to use a dung bomb at this time which lasts for about a minute.
If the Khezu is inside a cave, and doesn't feel like fighting you, it will scurry to a dark hole in the cave, drop, and fly into the darkness.