
I. Overview
Hero Story : A darkness who was ancient even in the early days of the world's existence, Mercurial is the embodiment of rage and vengeance in the souls of those long dead. Haunting her enemies with relentless fervor, she is able to throw a dagger-like projectile that allows her to chase her prey beyond physical boundaries, and the fear and the desolation struck in the hearts of those who have the misfortune of encountering her alone is a pain impossible to withstand. Spectre's thirst for destruction is insatiable, and the upcoming struggle seems to be just what she was waiting for.
Attributes :
Str = 19 + 2.0
Agi = 23 + 2.2
Int = 16 + 1.9
Attack Range = 100 (melee)
Movement Speed = 295
II. Skills Overview
Spectral Dagger

The Spectre launches a deadly dagger that trails a Shadow Path. Deals damage to the targets in its path. Units hit by the dagger will also trail a Shadow Path. The Spectre becomes phased (gains zero collision) while on the path.
Level 1 - Spectre gains 5% ms, enemies lose 5%. Deals 50 dmg.
Level 2 - Spectre gains 9% ms, enemies lose 9%. Deals 100 dmg.
Level 3 - Spectre gains 14% ms, enemies lose 14%. Deals 150 dmg.
Level 4 - Spectre gains 18% ms, enemies lose 18%. Deals 200 dmg.
Cooldown: 25 seconds.
Level 1: 130 mana, 25 sec cooldown.
Level 2: 140 mana, 25 sec cooldown.
Level 3: 150 mana, 25 sec cooldown.
Level 4: 160 mana, 25 sec cooldown.
Comments : Great skill for escaping and chasing. Zero collision will enable you to move through creeps, heroes, trees, and even hills. If you targets a unit it will follow the unit and stop at that unit, but if you target area or land it will go straight and stop after a long range. The trail will create for every hero that hit the dagger. Target hero to chase and target land to kill creeps and harass multiple heroes
Desolate
Deals bonus damage that cuts through armor when attacking a hero that has no nearby allied units. Works on Illusions.
Level 1 - 15 Bonus Damage.
Level 2 - 25 Bonus Damage.
Level 3 - 35 Bonus Damage.
Level 4 - 45 Bonus Damage.
Passive
Comments : Powerful attacking skill. Very useful in one on one situation. It's still effect when creeps are away about 300 range, so use it wisely. Cut down armors are very hurt
Dispersion
Causes any damage taken by Mercurial to be reflected onto all enemies in a 1000 AoE.
Level 1 - 5% of damage.
Level 2 - 10% of damage.
Level 3 - 15% of damage.
Level 4 - 20% of damage.
Passive
Comment : Gives 20% of damage taken to enemy 1000 AOE is hurt enough. But it's for additional damage only (it doesn't reduce any damage got)
Haunt (Ultimate)
Creates a haunting image beside each enemy hero. These images are uncontrollable, take 200% damage, deal 50% damage and each of them will attack only its pair. Cooldown goes down with level.
Level 1 - Lasts 4 seconds.
Level 2 - Lasts 5 seconds.
Level 3 - Lasts 6 seconds.
Cooldown: 150/120/90 seconds.
Level 1: 150 mana, 150 sec cooldown.
Level 2: 150 mana, 120 sec cooldown.
Level 3: 150 mana, 90 sec cooldown.
Comments : Rather weak ultimate. But very powerful after the items are built. Haunting also haves desolate and dispersion, some item effects still goes on (like radi, SnY, boots, etc.). Reality to replace the haunting with real Spectre. Use it for killing (similar to zeus), surprise ganking (ganking from fountain? That's a surprise), confusing (at war...), escaping (it's hard although...)
III. Build
Skills Build
Level 1 : Desolate
Level 2 : Spectral Dagger
Level 3 : Desolate
Level 4 ~ 5: Spectral Dagger
Level 6 : Haunt
Level 7 : Spectral Dagger (Maxed)
Level 8 ~ 9 : Desolate (Maxed)
Level 10 : Dispersion
Level 11 : Haunt
Level 12 ~ 14 : Dispersion (Maxed)
Level 15 : Attribute Bonus
Level 16 : Haunt
Level 17 ~ 25 : Attribute Bonus (Maxed)
Items Build
Core Items :
Power Treads

Explanation : It's far more better to Spectre to have PT than BoT. Faster aspd will makes your desolate come often, also increase your haunting's power. Get this ASAP
Radiance

Explanation : Do I have to explain this? For information, hauntings WILL also get RADIANCE effect. Also it will helps you to kill creep for desolate. Also it can combine with dispersion for great damage.
Sange Yasha

Explanation : Great item for Spectre although not as good as radiance. This will gives you 15% aspd (more with +16 agi) and ms that is both needed for Spectre. Maim also help's Spectre in chasing and makes illusion more powerful.
Butterfly

Explanation : It isn't that recommendable. But it's useful enough. Buy it after radi and SnY will give great impact. The aspd it gives is great enough for Spectre
Alternative Items :
Diffusal Blade

Explanation : Increase the Spectre's chasing skills by purge also gives mana burn ability to Spectre and hauntings. But SnY is better.
Manta Style

Explanation : Don't Underestimate it's power. Use this is an option if you face against hero that likes to jumps in such as Mortred, SA, Mirana, etc. When they jumped in, create illusions => dagger => attack. All illusions WILL HAVE DESOLATE and DISPERSION. So, illusion will deals 2x33% of Spectre's damge + 2x55 desolate damage that cut armor. Means you'll deal 167% damage and 165 damage that cut armor. It's very hurt. Also with haunt, you'll deal 217% damage and 220 desolate damage. IT'S MORE THAN DIVINE!!! But, in normal game, it's hard to get desolate damage in all illusion, because enemy won't be alone that often...
Battle Fury

Explanation : Use this to makes your desolate more often. This will kill the nearby creeps easier and makes your desolate works in a quick time. Also the damage it gives and it's hp and mana regen isn't waste for spectre. But, radiance is still better.
IV. Strategies
Early Games :
Desolate is powerful at early level. Lure one on one situation and hit it. Don't directly attack the enemy because it will makes creep hit you and disable your desolate. Get near of him/her and then hit. One or two attack of desolate will hurt them. In most of case you'll win. From lv 4 to 7, Spectral Dagger are maxed to chasing. After you get haunt keep your eyes at your enemy's hp in other lane and use haunt => reality => dagger properly, you should get 2 to 5 kills depends on your enemy. In level 9, try to get kill as much as possible.
Middle Games :
Now, it's time to collect some money. Don't go for jungling, you better farming in lane with 1 portal (in emergency, dagger to forest => run into forest => portal will save your life). Also get some kills too, nevertheless, he's a killer. Buy sacred relic if possible. If not, try to make SnY or diffusal blade.
Late Games :
You should have Radiance or SnY by now. Try to have both of them. You'll get a great killer for your team. Now, you could buy some luxury item and your team will win the game.
V. Allies and Enemies
Good Allies : Heroes that can clear out creep fast (Ezalor, Sniper, Treant) or makes/lures enemy alone (VS, Pudge, Earthshaker).
Bad Enemies : Heroes that creates illusion (TB, Siren, Nessaj, Meepo) or units (Lycan, Syllabear, Furion). Also heroes that can inflict long stun or perma-bash (Jahrakal, Magina, FV)