From Dota 2 Wiki
| Faerie Fire|
|The ethereal flames from the ever-burning ruins of Kindertree ignite across realities.|
- When randoming a hero, the hero starts with a free, unsellable Faerie Fire.
- Faerie Fires do not stack in the inventory. Each bought instance requires its own slot.
- The attack damage from multiple instances fully stacks.
- Faerie Fire is not shareable and cannot be used on allies.
- Interrupts the user's channeling spells upon cast.
- Faerie Fire is often purchased as a ranged equivalent or cheaper substitute for
- For the mid-laner, Faerie Fire can create an advantage over the enemy, as well as save him from a gank.
- When diving past a tier 1 tower in the laning phase, a Fairie Fire can restore enough health to withstand one more tower hit, which can help you get the kill or retreat if need be.