From Dota 2 Wiki
|A hammer forged for the gods themselves, Maelstrom allows its user to harness the power of lightning.|
- Does not stack with the Chain Lightning of Mjollnir or other Maelstroms.
- When obtaining multiple items with the Chain Lightning ability, only the one that has been continuously the longest in the inventory works.
- The lightning bounces in 0.25 second intervals, so hitting max targets takes 0.75 seconds.
- Can never hit the same unit twice per proc.
- Can only proc on successfully hit attacks, thus missed attacks cannot proc.
- All bounces together can deal up to 480 damage (before reductions).
- Chain Lightning can proc while a previous chain lightning is still bouncing.
- Chain Lightning uses pseudo-random distribution.
- The Maelstrom Chain buff is a hidden buff required for the lightning to jump.
- Chain Lightning does not use a regular cooldown. It is neither displayed on the item icon when proccing, nor is it affected by cooldown manipulating effects.
- Chain Lightning increases Sniper's farm speed, allowing Sniper to get more items quickly as a carry.
- Sniper's long range from Take Aim allows him to safely clear waves. This makes it an essential item in base defense situations.
- Alchemist's increased attack speed while in effect of Chemical Rage increases the chances of Chain Lightning proc, increasing the item effectiveness even more.
- Works well with Focus Fire.
- Maelstrom is the third most cost effective DPS item in the game after Mask of Madness and a Diffusal Blade (agility heroes).
- Maelstrom is a very good item for speeding up farming. If the extra experience is not needed, it is good alternative to the Hand of Midas. Since the lightning has a huge bounce range, it can be used to damage multiple camps at once when farming in the woods, if vision over the camps is present.
- It is also great to deal with illusions or mass-summons like Broodmother's spiders, Nature's Prophet's treants, etc. Especially useful for ranged heroes that lack area damage, since they cannot make use of cleave.
- The Chain Lightning deals magical damage which ignores armor and Damage Block, making it good against heroes that get a Vanguard, or Tidehunter with his Kraken Shell, and against heroes with high armor like Dragon Knight or Terrorblade.
- Consider buying an Infused Raindrop to counter Maelstrom's Chain Lightning damage.
- The maelstrom is effective to defend against mega creep.