The Lion is a ranged attack hero with intelligence as his main attribute (18 + 3.5). He is one of the three most popular characters, in the second place, according to DotaBuff, and played usually as lane support or as a free-ranging ganker. His abilities Earth Spike and Hex can take enemy heroes out of the fight for a while, blocking their abilities and movement for long enough to kill them. And with his ultimate ability Finger of Death, which deals tremendous magic damage, the Lion becomes a very unpleasant opponent able to kill others with a single click. Depending on his gear, he can step into a variety of roles: Disabler, Initiator, Nuker, or Support.
The Lion has poor armor, health, and movement speed, which makes him a soft target for ganking at the early levels. He is also useless against enemies with magic immunity. The hero can only show his full potential at the correct map position, and buying Blink Dagger will help him get either into or out of fights in the late game.
The Lion is an awesome ranged attacker, well-suited to ganking shots. Earth Spike and Hex make him a formidable disabler, and Finger of Death gets stronger with every kill. His Mana Drain interferes with enemy heroes’ spellcasting and helps replenish Lion’s own mana pool.
The Lion needs to be played aggressively. He should try to hassle the enemy to the maximum from the get-go, so on the lane he ought to invest in Earth Spike, which inflicts damage and stuns, and Mana Drain, which steals mana from enemies or neutrals and keeps the Lion camping on the lane with hardly any need for mona restorers. Together with Hex, which disables an enemy hero entirely, forbidding him to use spells or move, and some help from an ally hero with a strong magical procast or stunning in the arsenal, they will let the Lion score many kills. Finger of Death is considered one of the most powerful magic attacks in the game and does immense damage to a single target. Thus, the level 7 skill build should take the form of 4-1-1-1.
Being slow and working mostly as lane support or a roaming ganker, the Lion can benefit from Tranquil Boots that improve movement speed and health regeneration. A Magic Wand will increase all attributes. If the Lion’s team is doing well in the early game, he can try to save gold towards a Blink Dagger that will let him quickly get near an enemy hero and immobilize him for a nice gank. Items such as Aether Lens and Aghanim's Scepter extend ability range and the power of the ultimate skill. Getting a Ghost Scepter will protect the Lion from much physical damage and improve his chances against heroes who specialize in it.
The Lion’s low starting speed should be improved with a 10th level right +15 to movement speed talent. At the 15th level taking a left +70 to maximum health per Finger of Death kill is a wise investment in late-game survival. At the 20th level the left +20 to Finger of Death per kill talent is a good choice, especially if he has a complete Aghanim's Scepter that makes it an area-of-effect skill. For the 25th level the choice will depend on the game situation, but most players take a right talent that improves Earth Spike distance by 800.
The Lion’s disabling skills that keep heroes held are dangerous to all frail, low-health types in the early game. He is also good against any hero who relies on his abilities because Mana Drain can empty the opponent's mana pool. DPC heroes who have to stay on the battlefield for a long time become easy prey for the Lion, for he can disable them or kill outright with his ultimate skill unless they magic immunity.
The Lion’s poor health total is a potential problem when facing heroes who can instantly do massive damage, like Tinker or Nyx Assassin. The Lion also struggles against heroes with magic immunity or silencing, like Lifestealer, Silencer or Puck, because the Lion depends on his abilities a great deal. Being a slow walker, the Lion can be easily stunned or trapped for a short while, e.g. with Sacred Arrow from Mirana or Split Earth from Leshrac. Any character with a Black King Bar, Linken's Sphere, or Lotus Orb can negate the Lion’s abilities completely, take him out of the fight and even change the course of the game as a whole.
The Lion works best in a team as support and makes a dangerous ganker. Although his health, armor, and movement speed all work against him, he can dish out a great deal of damage himself or hold enemies in place for a time, letting allies with procast or strong instant-damage skills take care of them. A Blink Dagger should be gotten early if possible – it will make the Lion a very useful and ubiquitous hero, dangerous to the other side and eventually single-clicking enemies to oblivion.