Welcome to my Guide to Lord Dekain - The DoTbringer.

Lord Dekain is a Hero mostly focused around DoTing your Enemys to Death with his Passive, Q and R, but also clearing Minion Waves pretty fast to stomp the Lane, leaving not much of a choice for his Opponent, making him a hard Opponent to fight against, but let's get to the actual Stuff.

Festering Plague

Passive: Lord Dekain's abilities and every fifth basic attack add Plague Tokens to enemies. Enemies with three Plague Tokens suffer from Outbreak, slowing them and dealing Magic Damage over time.

This will be one of your most used Tool to harrass any Enemy. It acts as 5th Skill, obtained in the very beginning.

Contagion

Lord Dekain hurls a mass of diseased flesh in the targeted direction. If it strikes an enemy, they take Magic Damage over time. if the enemy dies while Contagion is still active, it will spread to another enemy nearby.

Your Bread and Butter Skill. It will clear Waves fast, do decent Damage while also never Ending as long as the Target dies and another is around, you probably won't run out of Mana very soon.
It's a Skillshot though, it may be hard to aim at Enemys.

Choking Breath

Lord Dekain exhales a large gust of infectious air in a cone around him. Enemies within the cone take Magic Damage and are silenced.

Besided having decent Damage, this is Long Ranged and also Silences every one struck, a must have against any Ability Heavy Hero

Swarm

A swarm of insects seek out nearby enemies with Plague Tokens, dealing Magic Damage as they burrow into flesh.

As said in the Description, this Ability will be avaiable once your Target has a Plague Token, this will also act as a Bridge to your Passive Proc on Level 1 (if you decide to pick it), but will also be a good Tool, in Combination with Choking Breath, to deal with Minions.

Toxic Bile

Lord Dekain vomits a putrid stream of bile at a target location. Enemies within the bile take Magic Damage over time.

Can be tricky to use if the Opponent has the Blink Glyph, but will hurt if they don't. Loads of Damage ensured.

Depending on what you want to do first and how you want to play there are some Ways to go with:

Early Dmg

E -> Q -> W -> E -> Q -> R -> as you like

This Way relys on you utilizing your Passive. As soon as you hit 4 Stacks, Auto Attack the Enemy Hero. Since the Tokens will last a bit, you don't need to instantly hit E. Build up 3 more AA's, try hitting the Enemy Hero, use E (to reset the Attack Animation) and hit up that Last Auto Attack which sould be the 5th, procing your Passive. This will Deal a good amount of Early Dmg to force your Enemy Laner back asap, giving you a lot of Time to farm up and push your Wave to the Tower so he won't get anything from that juicy Wave.

Save Play

Q -> W -> E -> Q -> W -> R -> as you like

This gives you the Ability to push the Enemy Laner back to his Tower from the Safe Zone, probably messing with his Minion Score because he can't last hit properly, while also giving you an early Silence.

Not much to say here, it's personal Preference to set these, but i recommened putting Points into Special Power and or Health.

Blink

Since Blink let's you get out of Trouble very fast and you're not a tanky Champ, this is a must have imo. I'd go with the Low Cooldown and Resistance Bonus Path, but Long Range -> Resistance might work too. I wouldn't take Damage as it's insignificant and blows a bit of tankyness.


Anguish

The Main Thing i would take. It does considerable Damage and with the Upgrade Path Reduce Healing -> Amplify Other Damage, you're good to go against any Lifestealer, Spellvamper or Healer, while also doing more Damage with your Skills.


Bulwark

As a side Option for Anguish, i would take this. A good Baiting tool that also, provided you take the Path, will remove CC on a Low Cooldown while giving you a Shield. If you're more focused on helping your Team, go with Low Cooldown -> Team Shield.

Of course, these Builds can change and probably will but that's what i put together just now. I'll take any Suggestion to improve on those Guys :)

(if you don't have any Idea on what those Items are, go to Profile -> Heroes -> Pick any Hero -> Edit Hero -> Customize and search for the Items)

Your Main Lane will be Mid! Lord Dekain can work on Bot/Top too, but will have a harder Time.

Depending on what ability Sequence you're about to Pick, your Early Game might differ and so your starting Items.

Let me clear up Last Hitting first though, because this is an important Part of any MOBA:

Last Hitting a Minion is necessary to not push your Lane if you don't intend on going Berserk. Last Hitting requires a bit of Practice and Knowledge of how much Damage you will deal with your Auto-Attack. I suggest you train a bit with someone so you get the hang of it.

Early Damage

Early Game

Start with an Apprentice Wand and a Health Potion and put a Point in your E + take Blink as your first Glyph
As said in the Ability Sequence Segment, you want to hit the Enemy Laner every 5th Attack so he get's a Plague Token to use your E on, this way you're putting a lot of Pressure on him, forcing him back sooner or later. Keep Last Hitting Minions until he backs off, then push the Lane to his Tower to deny him any Creeps. If you can throw in some Kills, push the Lane and go back to buy Items.
You may gank a Lane as well, but don't waste Time if you suspect you can't really do anything.
Don't forget the Quests!

Item Order: Apprentice Wand + Health Potion -> Mage Staff -> Commoner Boots -> Circlet of Mana -> Soul Snare -> Hoarfrost Pendant

Mid Game

Your Time to shine! By now, your Soul Snare should be Orza's and you got dat Anguish. You need to be ready to use both of it. As soon as you think you can land a Kill, start out with Orza's Active and then your Passive Proc Combo which should be easier now because your Skills apply Plague Tokens as well, followed up by Anguish. If your Enemy Laner has the Passive Proc, they're most likely half Life now with some Skills still DoTing. Use Choking Breath to deny Skills and Glyphs. If necessary, Ult. Or you could use Bulwark to bait your Enemy Laner into thinking he could kill you, but really you're just mocking him if you go out Victorious because of that Bulwark.

Item Order: Finish Glacial -> Finish Acolyte Slippers -> Start building Tulaans or Sanctus

Late Game

Since Lord Dekain has good AoE Damage, multiple Enemies aren't a big Deal. W -> E -> Ult -> Q and they should peel down. Stay behind your Tank as you're not tanky, Fights should be fairly easy to Win that way.

Item Order: Finish Tulaans and/or Sanctus -> Build Defilers Touch

Safe Play

Item Order's will not differ from Early Damage, but you might change a bit depending on your Lane is going.

Early Game

Start out with Conscripts Wand + Health and Mana Potions and of course Blink. Use your Q on Minions and then keep hitting the Infected Minion but beware of Last Hitting! Push your Enemy to the Tower, denying him Minions. Keep doing this until 6, then you can try to take your Enemy Laner on.

Mid Game and Late Game are pretty much the same as in Early Damage since you'll be doing the same Stuff just starting your Game differently.

I love Lord Dekain for how he works and how destructive he can be and i hope this Guide may help you to feel the same as i do! :)
But the Guide pretty much ends here, if you have any Suggestions on changing something or just want to tell me i totally forgot something or was being lazy somewhere, don't fear to hit me up, i'll change that asap.