Hi! This is my first guide on Mobafire, and the reason why I was triggered to do this is because I've insta-bought all new heroes since Skarner, and none of them has felt so good to play as Xerath did.

Xerath is a long-range mage (in fact, the longest range in the whole game), but his range comes with a damage compromise. He's not as good a nuker as for instance Brand, but he can out-range him pretty well, and this build makes him way less squishy than Brand would ever be.

This build is optimized for mid-lane 1v1. The focus is to get a high AP quickly to compensate for the damage compromise that comes this champion.

...with Xerath

+ Longest range of the game
+ A lot of AoE
+ Excellent farmer
+ Excellent carry
+ Not the squishiest of spellcasters
+ Good at ganks, if needed for that
+ Really cool voice and cool look

- Not the highest damage output
- Useless in duels
- Hard to master for optimal damage
- Pretty chanceless in 2v1 (ie early-game ganks)
- Needs cooler skins

...with this build

+ High AP with a little anti-squish
+ Can out-range anything and stay away from trouble very well

- A little mana heavy, especially early-game

The runeset for this champion is pretty standard. Marks of Magic Penetration because that is the only primary mark that works for AP offense. Seals of Mana Regen because this build is suffering from low mana regen (not level-based ones, since this is the most noticeable early-game), Glyphs and Quintessences of Ability Power because he needs all the AP he can get.

Again, pretty standard for a spellcaster. There are some questions that might arise from this mastery tree:

Why not maxed Expanded Mind?

In my experience, mana regeneration is so much more relevant than maximum mana, unless you have an item build that relies on high mana for something.

Why not Insight?

If you're playing a team game with a lot of mana heroes, then this could be a good pick. For public play though, most mana-dependent heroes have builds that handle their desired mana usage.

Why not Blink of an Eye?

Rarely is anyone in a spot where Flash would have saved you, but you had 15 seconds (or less) left of the cooldown.

Choices up for Change

If, by any reason, you would prefer one of the above masteries instead, here's what I would compromise:
1. Greed. This hero is an excellent farmer, and will do fine without it.
2. Quickness. Although a slight movement speed is nice, if you play this hero right, you won't need it that much.
3. Expanded Mind. If this isn't the spell you're compromising for, I'd even be prepared to drop these two points.

This.
Build.
Needs.
Clarity.

To optimize damage output, the items are focused on ability power, therefore this hero relies on his Clarity spel. I guess if you feel strongly for another summoner spell, I'd compensate by purchasing Tear of the Goddess early game, and skip Doran's Ring.

Flash speaks for itself. Best summoner spell of the game.

Here is a list of other summoner spells (in order of relevance), and why I don't pick them:

Ignite - Good spell for this hero, but the range of it is just too short. Since this hero relies on keeping the distance, you rarely get to use this efficiently.

Exhaust - Same as above. You're rarely the one chasing a hero anyway, and if you are, you're much likely able to reach him with your spells to finish him off anyway.

Ghost - If played properly, you sort of have a built-in ghost ability with this champion, when exiting your Locust of Power.

Heal - The main goal is to not put yourself in a situation where you will need this. But if you're targeted a lot, and if you like the spell...

Other spells are just not even up for discussion...

Xerath's passive, Ascended Form, is what gives him potential to be not-so-squishy. A high AP boost, which is required for this hero, will grant him armor, and adding just a little health to that, he will not be the most optimal target for an AD enemy.

This chapter is a no-brainer. Start with maxing out Arcanopulse (Q) since it's his main attack (longest range, highest damage, lowest cooldown, multiple targets), and add Locus of Power (W) after that. The main reason to level your W is for the cooldown reduction (at level 5, the CD is equal to the CD of Q, which gives you constant long range, constant extra magic penetration, and constant speed boost when you're not firing). Last but not least, Mage Chains (E), which is mainly used for stuns early-game.

Also, would like to point out that the ulti, Arcane Barrage (R), is one of the best ultis out there, if used properly. When the enemies are clumped up and pushing (or trying to gank one of your team mates), this spell will do tons of damage. Try to hit 2 or more champions with each blast at all times (except for when you're using it to finish someone off).

First item to get immediately is Doran's Ring, for the AP and mana regen boost. Due to Clarity, this is the only mana regen you will need for a while (you might end up in a situation without mana every once in a while, but it will likely not cost you the game).

As for the boots, I choose Mercury's Treads because the MR is a good compliment to the health and armor the later items grant. But if you like Sorcerer's Shoes or Ionian Boots of Lucidity better, then by all means! In my opinion though, you already have extra magic penetration from Locus of Power, and the mana-heavy build will probably not allow you to efficiently use less cooldowns early-game.

Secondly, I go with Rylai's Crystal Scepter, for a few reasons: First of all, the health is a great compliment to the armor boost from the passive, secondly, it will make your Mage Chains slow your opponent, which makes it easier to hit them with Arcanopulse, and thereby stun them. Thirdly, when someone's fleeing the battle, your Locus of Power + Arcanopulse is the most likely way of being able to hit them, and if that attack slows the enemy champion, your team will be able to catch them.

After that, there are a few options. If you find yourself targeted a lot, and your team and/or the enemy team is AP heavy (especially if both are), you could consider getting Abyssal Mask instead of Mejai's Soulstealer (which isn't very efficient if you die a lot), which will compliment your health and armor boost with more magic resistance. The -MR aura works great too, as long as the enemy team stays close to you.

If that's not the case though, you should lay everything you have on AP, starting with Rabadon's Deathcap, which is the best AP item in the game. If you feel like you're doing well with the damage you're dealing, I would even consider getting Mejai's Soulstealer even before Rabadon's, due to its cheap price and its stack. That will benefit you late-game.

The last item, Deathfire Grasp, is for very late game, but due to the farming skills of this hero, you're very likely to get there. As you might notice, this is the 7th item in the list, so if you're getting this, sell Doran's Ring. I chose this item to compensate for the mana regen of the ring, and also, the active is a very cool complement when you have loads of AP.

I would NOT get two of any big items, like Rabadon's Deathcap. I just don't think it's worth the extra gold when you're not getting the passive twice.

As mentioned, this build is optimized for mid-laning. Early-game, this hero is awesome (probably the best) at harassing the enemy with Arcanopulse. The low cooldown allows you to fire a lot, and you can always stand behind your own and the enemy minions while firing for simultaneous protection and farming. Locus of Power won't be that good in the beginning, since the cooldown is sort of long, but an enemy that is low on health and fleeing back to its tower will need to think twice.

Regarding Locus of Power (W), there are a few things to have in mind:
While in the lane together with your opponent, never remain in the immobile state for long. Just use it to fire the long shot(s), then deactivate it, otherwise you're making the skill shots so much easier for the opponent. However, when your opponent is missing/dead/healing, and you're harassing the opponent's tower, go to the immobile state and remain standing like that for as long as possible. That way, if someone tries to gank you, or the enemy team's mid-laner gets back, you can toggle it off and use the speed boost to flee back.

With this build, I claim that in a 1v1 lane, you will always have an advantage against your opponent, due to the range. The only way to beat this is if the enemy team has a jungler that ganks a lot. But even then, this hero is in a good spot because of the distance he is always able to keep.

In later game, the best sequence of attack is:

Locus of Power + Mage Chains + Arcanopulse (stun) + Arcane Barrage + Arcane Barrage + Arcane Barrage + Arcanopulse

You will have time to do this in one single LoP. When pushing, I recommend keeping your distance and just repeating Locus of Power + Arcanopulse as often as you can (every 4th second at lvl 13) until you get into a big gang fight. That's when you choose your target (that is in the middle of the enemy ball) and fire away.

NEVER GO OFF ALONE! This hero is useless on his own in late-game, so make sure you stay with your team (or at least your tank) at all times.

So I guess this guide is pretty standard, but it's not the guide that makes this build unique and good, it's the hero. This hero immediately became my new favorite after having played mainly tanks ( Shen) and mages ( Brand).

Hope this grants you as much success as it has to me!