Lone Druid

Lone Druid is an adaptable and versatile Agility Hero, who summons a Spirit Bear, who has a set of skills and can equip items, as his ally. With the help of his Spirit Bear, he can Carry, Jungle, and Push lanes effectively. Because of these, technically speaking, The Bear and Lone Druid himself, are two available heroes at once. The Bear is mostly played as the Tank and Aura giver, while the Druid is played as the Support and the main Damage Dealer, but the Druid is still capable of causing more damage, even more than the Bear, and when he activate his spells, it will not only buff him but the Bear too. Lone Druid is versatile as he can change from a fast ranged warrior to a tough and mighty melee Bear himself. Together, they can push the lanes effectively, farm Neutrals in a cinch, and can take down Roshan early if equipped with the right items. Because players will have to control him and the Bear and you will use the skills he and his Bear has, Lone Druid will be tough and difficult for newer players. Lone Druid is recommended for expert players.

Spirit Bear
Spells last as long on Spirit Bear as they do on heroes.

Various mechanics
Mana
 * Unlike Animal Courier and Flying Courier, Spirit Bear can obtain mana from items directly increasing mana pool.
 * Natively Spirit Bear seems to have a bit less than 0.1 mana regeneration, modifiable by % mana regeneration items and direct mana boosts.

Items cooldowns
 * Sylla and Spirit Bear operate on 2 completely separate sets of cooldowns.
 * Once item is activated, cooldown does not change upon moving to other inventory (hero has cooldown on item and simultaneously instance of item has cooldown of it's own), example:
 * Lets say you have 2x Dagon,
 * Use 1st on Sylla and 2nd on Spirit Bear,
 * When you move both to Sylla's inventory, cooldowns are still displayed separately,
 * Let's say you put 3rd Dagon into Sylla's inventory,
 * You see two Dagon displaying same cooldown (1st uses both hero's and item's cooldown while 3rd displays only hero's cooldown), while 2nd is displays it's own cooldown,
 * When you move 3rd Dagon into Spirit Bear's inventory you will see it displaying same cooldown as 2nd instead of 1st.

Hand of Midas
 * Double Hand of Midas is a bug (should be courier version) and will be fixed shortly.

Gem of True Sight
 * Gem of True Sight does not reveal invisible units when held by Spirit Bear.
 * Spirit Bear still drops it on death.

Aegis of the Immortal
 * Spirit Bear cannot pick up Aegis of the Immortal, but can attack (destroy) it.

Runes
 * Spirit Bear can destroy runes, as can any other unit. However, Spirit Bear can also use runes, which is a glitch.

Trivia

 * Lone Druid's original mane was Syllabear, a pun on the word syllable, but it is now shortened as Sylla.
 * Lone Druid, while on True Form, used to have a second sub-skill called One, it equally distributes the damage taken by Sylla and the Spirit Bear, allowing them to endure more damage and live longer.