Eye of Skadi

There is no item in Dota 2 that gives you this much across this many stats simultaneously. Thirty-five strength, thirty-five agility, thirty-five intelligence—every primary attribute in the game, in the same slot, at values that translate to nearly 500 extra effective HP, significant mana pool expansion, armor from agility, attack damage scaling on your primary attribute, and attack speed. The wiki calls it the most across-the-board stat item in the game, and it is simply correct. For heroes who need everything — tankiness, damage, mana — Eye of Skadi is the one purchase that delivers all of it together rather than solving one problem at a time.

Then there is Cold Attack, which is doing two completely separate jobs passively. The movement speed is slow—50% on ranged heroes, 20% on melee—meaning every attack you land makes the target easier to chase and harder to kite you with. And the 50% health restoration reduction, buffed in 7.41 from 40%, means every single source of healing the target has is cut in half for 3 seconds after each hit. You are right-clicking a Huskar building with Armlet—his lifesteal from Berserker's Blood is 50% less effective. You are hitting a Gyrocopter with Satanic—his lifesteal is 50% weaker. You maintain that debuff indefinitely as long as you keep attacking, which against heroes whose survival plan is built around regeneration is effectively a permanent anti-sustain aura.

Fourth or fifth item on ranged carries and universal heroes who need both tankiness and damage in the same slot and are fighting into sustained late-game scenarios—Medusa, Spectre, Phantom Lancer, Drow Ranger, Naga Siren, Arc Warden, Morphling, and Weaver. The timing is 35 to 45 minutes, after your core offensive foundation is complete.

The draft signal is a healing-heavy enemy lineup or a game going so late that your physical damage is being mitigated by high armor and you need the stat package more than another weapon. Against Huskar, Alchemist, or any hero whose fight durability depends on regeneration, Skadi's 50% restoration reduction stacks with Spirit Vessel from a teammate into near-complete healing negation. Against high-armor targets, the 35 agility adds armor to you while the slows keep them in range long enough to actually die.

Illusion heroes buy it specifically because all 35/35/35 stats feed directly into every illusion simultaneously—the Cold Attack proc is personal and does not apply from illusions, but the tankiness and stat-based damage boost on a Phantom Lancer with eight illusions is enormous.