DotA Orb Effects

Item orb

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Special notes on ranged:
Cold Attack isn't really an orb effect on ranged units, it only adds a debuff on hit to your attack, and as WC3 is coded, each attack may only place one debuff each attack. This leads to some special cases with Cold Attack on ranged:

Feedback and Cold Attack: If the target has mana, feedback will take effect. Otherwise, Cold Attack will take effect.
Chain Lightning and Cold Attack: If Chain Lightning activates, Chain Lightning will take effect. If Chain Lightning doesn't activate, Cold Attack will take effect.
Maim and Cold Attack: If Maim activates, Maim will take effect. If Maim doesn't activate, Cold Attack will take effect.

Hero orb effects

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A quick explanation on how to read an excel chart:

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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 that the priority order is left over right, up over down. (upper left slot is thus highest priority, upper right slot next in priority, middle left after that, and so on)