Dota 2/Ezalor the Keeper of the Light

""Ezalor...I think that's my name.""

Keeper of the Light, usually abbreviated to just KotL or Ezalor, is a ranged intelligence hero who can be played as a support and a pusher. He can push lanes continuously and support his teammates in need. His Illuminate will be his most used spell, as it will be what he uses to push lanes most of the time. It is also rather effective as a damage spell, but its long charging time makes it not very practical. He can be great partners with a spellcaster due to Chakra Magic, ensuring that him and his teammates will never be starved of mana. He can also be an annoying foe against spellcasters with his Mana Leak, which makes life difficult for positioning-heavy intelligence hereos. His Spirit Form is one of the longest self-buff abilities, making charged Illuminates easier to unleash. It also gives him Recall, for saving allies and Blinding Light to counter carries. Keeper of the Light might seem like any other support hero, but his great ability to push makes him one hero to watch out for.

Illuminate
Illuminate gains damage with each second it is channeled. Once the maximum channeling time is reached or it is released early, it will send a wave of light that deals damage to anything in its path. While it does have to be channeled, it can do more damage than other similarly leveled spells, up to a humongous 500 at level 4. Most of the time you will be using it to push lanes, as its trajectory lets it sweep away entire creep waves. It is also decent for dealing damage, though it is best cast behind the main battle, as enemies seeing you channeling it will usually dodge the wave or interrupt you with a stun.
 * Ability: Channeled, Target Point
 * Damage Type: Magical
 * Damage Per Second: 100
 * Radius: 400
 * Range: 1600
 * Max Channel Time: 2 / 3 / 4 / 5
 * Mana Cost: 150 / 160 / 170 / 180
 * Cooldown: 10

Release Illuminate
Releases Illuminate early.
 * Ability: No Target

Mana Leak
Mana Leak is similar to Bloodseeker's Rupture, but it drains mana instead of health. Affected units will have a portion of their max mana drained for every 100 units they move, and will get stunned if they lose all of their mana. While the spell does nothing if the target just stands still, most spells require some positioning to land, while targets also have to be within the cast range to be able to cast it. That means it is very annoying for spellcasters, especially positioning-heavy heroes like Windrunner and Jakiro.
 * Ability: Target Unit
 * Affects: Enemy Heroes
 * Leak Duration: 4 / 5 / 6 / 7
 * Mana Leak Percent: 3.5% / 4% / 4.5% / 5%
 * Stun Duration: 1.5 / 2 / 2.5 / 3
 * Mana Cost: 75
 * Cooldown: 16

Chakra Magic
Chakra Magic restores a set amount of mana for the target. It is a simple spell, but one that you, and any other mana-intensive heroes on your team, will find extremely helpful. More mana means being able to cast more spells, and at times it might just be enough to let a teammate cast a spell that your team desperately needs. You can also use it to give you free mana, since it costs less mana than it restores to use it.
 * Ability: Target Unit
 * Affects: Allied Heroes
 * Mana Restore: 75 / 150 / 225 / 300
 * Mana Cost: 25 / 45 / 65 / 85
 * Cooldown: 19 / 18 / 17 / 16

Spirit Form
Spirit Form buffs up your Illuminate, letting you move freely while a spirit channels it for you, as well as giving you two new abilities. It might seem like a lackluster self-buff ultimate, but it lasts for a very long time. The improved Illumination means you can push lanes with ease. All these abilities also make you a better contributor in teamfights.
 * Ability: No Target
 * Duration: 40
 * Mana Cost: 100
 * Cooldown: 80 / 70 / 60

Recall
Recall teleports the target to your location after a short delay. It can be used to teleport a critically-wounded ally to relative safety. It can also be used to quickly return a hero who was purchasing items or healing up at the fountain back to the frontlines quickly. Lastly, you can use it to get assistance when pushing lanes.
 * Ability: Target Unit
 * Affects: Allied Heroes
 * Teleport Delay: 5 / 4 / 3
 * Mana Cost: 100
 * Cooldown: 15

Blinding Light
Blinding Light creates a huge flash that blinds all enemies caught by it, knocking them back and making their attacks miss. It has a wide radius which makes it quite useful during teamfights, though there are better initiation spells. The miss chance debuff helps reduce the threat of the enemy carry temporarily, while the knockback can knock foes out of position or isolate a hero from their teammates while your team takes it down.
 * Ability: Target Point
 * Radius: 675
 * Duration: 3 / 4 / 5
 * Miss Chance: 80%
 * Knockback Distance: 250
 * Mana Cost: 50
 * Cooldown: 20 / 16 / 12

Standard support build
Get Illuminate at level 1, and be sure to max it by level 7 as it is your main source of damage and lets you push. Max Chakra Magic second as it will let you spam Illuminates or help mana-starved allies. Mana Leak is usually maxed last, although you can put one level into it early on for opportunate kills with its stun. Get Spirit Form at the standard levels 6, 11 and 16, though you can delay getting the first level if you want to max out Illuminate and Chakra Magic sooner.

Suggested Item Build
Being primarily a support, Keeper of the Light will usually want to focus on utility items. However, his ability to push can sometimes leave him with more gold than most supports get, letting him buy some for himself.

Starting items
Starting items are standard. Get a courier and/or wards if nobody else has bought it, and get any combination of Tangoes, Healing Salves and Iron Branches. You might also wish to get a Gauntlet of Strength to increase your survivability.

Early-game items
A Magic Stick into a Magic Wand is a cheap item for emergency restoration. You also want to get Boots of Speed for your future boot upgrade. A Bracer is useful to improve your survivability and provide a good mix of stats, while a Ring of Basilius is good for pushing and also increases your mana regen.

Mid-game/Core items
Upgrade your Boots of Speed into Tranquil Boots, as it's cheap and comes with a useful heal, not to mention being able to disassemble it to make a Mekansm later. Arcane Boots is another decent upgrade, but Chakra Magic makes its ability a bit redundant. A Mekansm is a great utility item for your team, useful for pushes and teamfights.

Luxury/Situational items
A Pipe of Insight is another good utility item, reducing the damage your team takes during skirmishes. An Eul's Scepter, a Rod of Atos or a Scythe of Vyse are excellent but expensive late game disabling items. A Force Staff increases your health and mana regeneration, and also grants you a versatile spell for initiation and escape. If your team has a lot of momentum, you may consider getting a Boots of Travel which, coupled with Recall, can turn you into a pushing powerhouse.

Laning/Early-game
Keeper of the Light is commonly played as a lane support, though he still makes a decent solo mid due to his attack range and spells. As a lane support, try your best to deny creeps and harass your opponents while staying at a safe distance. Illuminate is a great support against gank attempts as well as for initiating a gank attempt yourself. A fully-charged Illuminate will take out a sizeable chunk of a hero's health, enough to stop a dive or let your allies finish them off. If your lane partner is mana-dependant, don't hesitate to cast Chakra Magic on them.

When playing solo mid, your ranged attack gives you an inherent advantage, but beware of ganks, since you lack any disables to help you escape and Illuminate charges too slowly without any allies to distract your enemies. Illuminate is great for pushing lanes whenever you wish to gank or go for runes. Mana Leak helps slow down enemy heroes during rune races.

Mid-game/Teamfights
Throughout the mid-game, no matter in ganks, pushes or teamfights, your Illuminate will be a useful asset. It can clear creep waves for pushing as well as act as a high-damage area of effect spell. During teamfights, you would want to always stay out of the center of the action, since you have poor survivability and are usually not farmed enough to withstand many hits. You should move in only to use support items or cast Chakra Magic and Blinding Light. Blinding Light is especially helpful for its blind effect, which can severely lower the enemy carry's output. You may also use Recall to teleport allies into a push or teamfight, and can be very effective if your team split-pushes frequently.

Late-game
Your strategy and role by the late-game is similar to the mid-game, but your Illuminate will start to lose its luster as a strong damage spell. It is still good for pushing creeps, but it will make less of an impact to well-farmed, tanky heroes. However, Blinding Light remains an excellent spell during skirmishes, due to the threat of hard-hitting carries.

Skill synergies
Chakra Magic naturally synergizes with the rest of your abilities since they all need mana to use. Spirit Form directly improves Illuminate by letting you move around after casting it while a spirit channels it for you. Blinding Light can also knock enemies into an Illuminate.

Hero synergies
Any hero that is regularly mana-starved like Earthshaker or highly dependant on mana such as Skywrath Mage would appreciate the mana granted by Chakra Magic. Carries, teamfighters and strong pushers can reach an important teamfight or push. Heroes with stuns and other disables can set up fully-charged Illuminates. Ancient Apparitions Cold Feet is particularly useful when used in conjunction with Mana Leak, as it either forces your target to remain in place and risk death or run and lose mana.

Countering Keeper of the Light
As Keeper of the Light has low base health and strength growth, not to mention being usually played as a support, meaning that he won't have many survivability items. That means he can usually be easily taken out if alone or out of position. Like most casters, Keeper of the Light is also vulnerable to any form of mana drain, silence or enemy magic immunity, as it will greatly limit his effectiveness in a battle.