General DiscussionHOW CAN I KNOW WHAT ITEMS AFFECT THE ILUSIONS?

Passive abilities that illusions can use:

Evasion
Critical Strike (it should be noted that the red number is before the illusion reduction)
Feedback (only works on melee illusions)
Movement speed (flat and percentage)
Attribute bonus (Strength, agility and intelligence)
Flat HP or mana
True Sight
Radiance burn aura (the aura still will not affect units already affected by a different Radiance aura)
Endurance Aura
Spell resistance from abilities, and base spell resistance
Demolish from Quelling Blade, Spirit Bear, or ASU Grow!
Permanent Invisibility
Barrage (Split Shot)

Anything else does not apply even if the animation appears. Several spells apply too, notable ones are Permanent Invisibility (Riki) and Counter Helix (Axe).

Someone mentioned otherwise recently, but Vanguard's flat HP bonus works on Spectre's illusions.

I think the big thing is simply that illusions don't get +dmg items but they do get +stat items so if building for illusions you want stuff like heart and butterfly and not stuff like deso and mkb.

Do cleaves work if they are spells? Like sven's?

You forgot una>

luna

Melee cleave doesn't work in any way, so nope to Sven or even Tiny. Psuedo Cleave in the form of Glaives and Split Shot works; although for split shot you need to activate it before Manta.

Another thing is that illusions benefit from the Yasha's raw attack speed (and anything it builds into) due to it being based off the Endurance aura from WC3 which increased attack and movement speed.

Edit: And also illusions will only gain the movement speed from a broken Tranquil Boots which give 60 ms instead of 90

To answer only to the items you asked
• [color=#9efffb]Daedelus[/color] - illusions can crit, the red number is before reductions e.g. a crit displaying 900 of a Phantom Lancer illusion that does 20% damage would hit for 180 damage.
• [color=#9efffb]Ring of Aquila[/color] - the illusions will benefit from the stats, but not the damage or the armour aura. Nearby non-illusion allies (including creeps) will benefit from the armour aura though
• [color=#9efffb]Drum[/color] - illusions benefit from the +9 stats, the aura (+5 attack speed and +5% MS) but not the +3 damage. The only auras that illusions benefit from are ones that give attack or movement speed
• [color=#9efffb]Desolator[/color] - illusions will not reduce the armour of enemies they attack even if you see red projectiles, the point of an illusion is to look as real as possible.
• [color=#9efffb]Butterfly[/color] - illusions will get the evasion and the 30 agility (30 attack speed and ~4 armour) but not the +30 damage or +30 attack speed.
• [color=#9efffb]Heart of Tarrasque[/color] - illusions will benefit from the +40 strength and the +300 HP, but not the 2% health regen per second.
• [color=#9efffb]Vanguard[/color] - illusions will benefit from the 250 HP, but not the 40/20 damage block for melee/ranged heroes, or the +5 HP regen. Illusions cannot benefit from any HP regen items actually.
• [color=#9efffb]Mekansm[/color] - illusions can be healed, but will not get the +2 armour. If the Mek holder is also the illusion creator, illusions will benefit from the +5 all stats Mek gives, but not the passive HP regen aura or the +5 armour.

Do illusions get attack speed off of butterfly or hyper stone? I'd assume they get the IAS off ac aura but not from the ac stats.

No for butterfly. So Ethereal gives illusions more attack speed than Butterfly.

No for hyperstone/AC either. They carry the aura, and units near them benefit, but the illusions themselves don't.

They don't get raw damage, armor or AS. They get raw HP, mana, stats and MS. Some spells work and some don't. It's random really. There is actually no reason for Axe illus to proc helix.

Zenoth, illusions benefit from any aura that gives attack or movement speed. Nothing else.

Quoted from http://dota2.gamepedia.com/Illusions#Auras_on_Illusions
"[color=#9efffb]In most cases, illusions will bestow the auras that the original hero has. However, with the exception of auras that increase Attack Speed or Movement Speed, they usually will not benefit from them.[/color]"

They will benefit from AC's attack speed, but will not gain extra armour from the aura. However, AC will still reduce the armour of nearby enemies thereby increasing the physical damage of the illusions.

androgynous, it's not cause an aura give attack speed that it work on illusion.

It's endurance aura that work, so drum and shiva's work on illusion (shiva from enemy) but assault doesn't work.

assault's aura is based on the one of basilus, not based from endurance aura.

"Another thing is that illusions benefit from the Yasha's raw attack speed (and anything it builds into) due to it being based off the Endurance aura from WC3 which increased attack and movement speed."
I'm not sure if this is entirely true. I think that Illusions mimic movement speed and attack speed in order to not trail behind when you move as a group, and to allow you to attack the same target with real and some illusions in order to make it not obvious which one is real by the animation. I don't think that Yasha uses aura rules in Dota 2.
Sure, that goes out of the window when the enemy attacks. But that means that they had to do something before using a single target stun for example.

People aren't going to be able to notice a difference in 15 attack speed. Yasha (and it's upgrades Manta or SNY) are the only items where the stat "attack speed" affects illusions. Gloves of Haste, Midas, Treads, et cetera, don't work on them.

Treads are definitely gotten on some illusion heroes such as Anti-Mage and Phantom Lancer to name two, and yet their illusions don't benefit from the 30AS, yet Yasha's does. And that's entirely due to Dota 2 keeping WC3 Dota parity, not to keep the attack time of illusions the same as the original hero, or else other attack speed items would also work on them.

The only movement based item that does not work on illusions is the active Tranquil Boots, illusions will always get the broken form's MS. Back when Tranquils had an active, the higher ms still didn't apply to illusions and you're telling me illusions mimic ms. If that was so, then Tranquils would've been fixed a long time ago.

edit: Well I stand corrected by Matrice about AC. Probably, I'll check in a private lobby to be sure
edit2: I was right, thanks for wasting my time planting doubts in my mind.

I didn't know they got as from drums or yasha.

Do you mean does it give them AS and armor or do you mean they carry the aura around with them? But either way both works I guess.

I have proof that AC's attack speed benefits illusions.
Here's the album.

I took several images as proof, here: http://imgur.com/a/VENij#0
I'll also explain the reasoning behind each screenshot

1. PL's starting attack speed is 123 due to having 23 extra attack speed from his base agility

2. PL with strength treads has 153 attack speed. 30 from Treads +30AS, and 23 from base agility

3. PL illusion has 123 attack speed due to not benefitting from the Power Treads attack speed. The image also shows that the true attack speed is displayed rather than a false one to misguide opponents.
i.e. it doesn't falsify the attack speed of the illusion as 153, so really attentive players can discern the real PL from the illusion by checking the attack speed stat.

4. Real PL with agility treads has 161 attack speed, 8 more than strength treads due to the agility.

5. PL illusion with strength treads has 131 attack speed, 8 more than the illusion which has 123, so that there's absolutely no doubt about attack speed affecting illusions besides from auras.

6. PL with only AC has 178 attack speed, 55 more than a PL with no items, due to AC granting 55 AS.

7. The illusion created, with an AC in it's inventory has 143 attack speed, 20 more than the 123 attack speed of an itemless level 1 PL, presumably from the AC aura (there may be some other unforeseen reason for it)

8. I created an illusion without the Assault Cuirass in it's inventory, and then picked it up on the real PL. The illusion still has 143 attack speed despite not having an AC in it's inventory, proof that the attack speed from the AC aura works on illusions because 2 illusions, one with the AC in it's inventory, and one without, both have the same attack speed.