*Note: This was original posted before by Malle, www.dota-allstars.com
*I think this guide is on of the best ever and show u how Orb Effects really works
Read the following text for your own benefit!
The two golden rules:
1: Orb effects will never stack.
2: You may only place one buff per attack.
And as an information sticker:
You will only get the effect that is listed in the box. If you get both, it says both. If there's some strange mechanics to it, it's listed in the legend.
Eye of Skadi will be a melee eye of skadi if the unit that picks it up is currently in melee form. It will be ranged if the unit that picks it up currently has a ranged attack. Switching forms may or may not affect the form of the Eye of Skadi, it depends on the ability that changes your range
Ursa Warrior is as of 6.44 a melee unit. Doombringer is a melee unit. As of 6.28, Banehallow remains as a melee unit in his ultimate form. Strength Morphling is no longer in the game.
Now, to the charts:
Click the image for a large view
Maim: "Sange", "Sange and Yasha"
Lifesteal: "Mask of Death", "Mask of Madness", "Helm of the Dominator", "Satanic"
Feedback: "Diffusal Blade", "Manta Style"
Chain Lightning: "Maelstrom", "Mjollnir"
Corruption: "Stygian Desolator"
Cold Attack: Melee: "Eye of Skadi melee"
Cold Attack: Ranged: "Eye of Skadi ranged"
Hero Attack Effects:
click the image for a large view
As seen in the ranged part, an Eye of Skadi and a Stygian Desolator would give you the Corruption orb effect, regardless of any other circumstances. However, on melee heroes, it says "Place". Looking in the legend, it tells you that "Place" means that the item in the highest priority slot will take effect, as well as the inventory priority order. I realize that my previous explanation may have been a bit ambiguous, so heres an image of the priority order:
BuffPlacer´s & Orb Effects
A buffplacer is something that will add a status effect to your target, visible in the status bar of the hero (where the buff icons are) whenever you attack him. Each attack may only add one buff to the target.
Eye of Skadi's effect adds a buff to the enemy, whether or not you're a ranged hero doesn't matter. So to be able to place that buff, Eye of skadi must be the highest priority buff placer. Frost Arrows add a buff as well, but is higher in priority than Eye of Skadi, so on any attack you use Frost Arrows, they would take precedence.
To check which of multiple effects will have effect, start by sorting out the orb effects, because orb effect buff placers have, so far, higher priority than non orb effect buff placers. Check which orb effect has the highest priority by comparing the first two against eachother, then take the dominant one of them and check it against the third. Repeat if needed.
Once it is clear which orb effect you would have, check whether or not it's a buff placer. If it's a buff placer, you do not need to check any further; that buff is the one you will add. If it's not a buff placer, or only a buff placer on some of your attacks, check whether you have any non-orb effect buff placers. If you do, check which one of them has highest priority, and then that buff will be the one you will place whenever your orb effect doesn't place a buff.
Of all the item orb effects, Corruption and Cold attack will always be buff placers. Both are orb effects on melee units, only Corruption is an orb effect on ranged units.
Chain Lightning and Maim are buff placers only when they trigger, but they are orb effects even if they do not trigger.
Lifesteal is only an orb effect; it is not a buff placer.
This means that with Lifesteal, you can have a non-orb effect buff placer work at the same time, on each attack.
With Chain Lightning and Maim, you can have a non-orb effect buff placer that will work whenever Chain Lightning and Maim does
not trigger.
With Eye of Skadi, on melee units, and Stygian Desolator you cannot have any other orb effect, nor any other buff placer.
With Eye of Skadi on ranged units, you could have an orb effect work together with it on each attack, as long as it isn't a buff placer.
Quick guide to item effect:
Melee
Priority--------Effect--Orb?----Buff?
1------------Lifesteal---x-----------
2------------Maim--------x-------*---
2------------CL----------x-------*---
2------------Corruption--x-------x---
2------------Cold-Attack-x-------x---
3------------Feedback----x-----------
Ranged
Priority--------Effect--Orb?----Buff?
1------------Lifesteal---x-----------
2------------Maim--------x-------*---
2------------CL----------x-------*---
2------------Corruption--x-------x---
3------------Feedback----x-------*---
4------------Cold-Attack---------x---
Same priority value means that place dictates which one overrides.
x means that it is that.
* means that it is that, only if the effect triggers.