Hello, my name is o0oAMCo0o, I'm an everyday, run-of-the-mill player who really enjoys playing Xerath! I'm not a pro nor am I going to pretend to have the absolute best guide to playing Xerath. What I do know is what works for me, so I wanted to share that with the community.

Xerath's farm is amazing...if you know what you are doing. Your farming is done SIMULTANEOUSLY WITH YOUR POKING. Here is how it works. A smart enemy will use their creeps as a shield, staying behind the bunch for safety. Poke through the creeps with your Q to t champ and use your W to push them back off of the mage-creeps. If positioned well you can finish off the back half of the wave with one set of your Q-W combo.

If the enemy is smart they will realize that they are giving you cs and poke at the same time. They will start to stray to the sides of their creeps, making your two-for-one less possible. This is EXACTLY WHAT YOU WANT! Now they are wide open for your stun to rock their world. you stun, auto attack so your passive can replenish your mana, then W then Q.

Congrats! You have officially learned how to be the most annoying midlane to play against ever.

(I don't have a computer capable of video capture or I would post a video of this technique. If I do end up upgrading my pc, I will get a video posted of this technique.

Xerath is 100% skill shot. This requires a lot of technical skill, but the benefits are really great. All of your abilities are just as much for CC as they are for damage. Throw down your Q and W to channel enemy champs where you want them to go. Here is a pretty decent montage of some of the skill shot benefits of Xerath. (not my video, credit to Sscherp on youtube)
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A word about Twin Shadows: This extremely underrated item is OP on Xerath. Your ult is all about seeing enemies who are far away and being able to hit them with your mortars. Twin Shadows reveals and slows your target, making them easy targets. THIS IS A MUST HAVE ITEM ON XERATH!

Lastly, please roam. Xerath's roaming capabilities (though deterred by his speed) are really essential for a successful team. Your ability to initiate from outside of danger is HUGE!

Xerath is the king of dropping huge amounts of unexpected damage through his awesome range. Skirt the outsides of the battles and unleash hell!