Introduction
This guide is intended towards players with some knowledge and experience on the workings of DotA. I won't cover basic things like last hitting and "strategies" for different parts of the game.

Skill Build

1. Impale
2. Voodoo / Mana Drain
3. Impale
4. Voodoo
5. Impale
6. Finger
7. Impale
8. Voodoo
9. Voodoo
10. Voodoo / Mana Drain
11. Don't learn Finger. Take it around 14. Learn stats instead. Don't learn Mana Drain either.

The rest of the skill build should be easy to figure out. The reason I don't take Finger at 11 is the bloody mana cost. 150 extra damage for 420 mana is not worthwhile when you are just level 11. You won't have full mana all the time. You are a gank hero and the extra mana is better on a blink+impale or blink+hex. Until you have sufficient mana then put a point on Finger. Same goes for level 16 finger. I only get it when I have around 1.5k mana pool.

For the unconvinced chaps, try it on a few games and see the difference yourself. Skirmishes work much better for me when I just have a level 1 Finger.

HP/MP pool from stats is more important than leveling the stupid Mana Drain. Level 1 MD is enough to supply your mana.

Item Build

Any item that supports MOBILITY is the top priority. These are some items Lion should have in no particular order. Boots of Travel are better than Treads but it's not practical until late game. So buy Treads in STR or INT. Phase is ok but I prefer STR/INT from Treads.

Must have, either one


Either Blink or Force: Any Demon Witch users without any of these items is not going to make use of his disables fully. Pathetic cast range from Impale/Voodoo coupled with your slow movement speed are going to hinder your performance in ganks. You are an initiator and chaser in small skirmishes. I hope I don't have to justify these items much. You can get both too.

Good to have


Urn: The charges and mana regeneration helps you roam the map without going back to base.

Janggo: Stats given are excellent. Aura burst are very useful for chases.

TP: You know it's good, but people always forget to buy one.

Luxury


Hex: There's no such thing as having too many disables.
Skadi: Build it only if you are filthy rich.
GS: Self explanatory.

Maybe


Medallion: Useful for taking down heroes fast.
BKB: Not limited to carries. You know when to get it.
Necrobook: Good for invisible heroes.
Shiva's: Self explanatory.

Using Lion

Impale is a powerful harassing tool. Hit it with a dying creep and an enemy hero. Hit him once or twice and then run because other enemy creeps will attack you. Unless your hands are quick enough to deter the aggression by attack+left click allied creeps.

Use Impale by clicking on enemy heroes directly. It will never miss unless your enemy is already moving away from your cast range before the Impale animation starts. The only time you click on the ground is when you are targeting multiple units.

Right after you Impale, immediately right click enemy hero before he fly up and then move towards him. Because of the casting animation time, your attack cooldown will reset, giving you 1 free hit.

Of course you can also use Impale right after Lion started throw his physical attack, saving time.

Stack stuns, that means estimate and wait for about 2.5s (0.5s air time) after hitting someone with Impale then use Voodoo. Adjust accordingly to your latency. Vice versa for Voodoo to Impale.

When there's 2 enemy heroes together and 1 of them can be killed with Impale+Finger, just kill that hero with Finger when the Impale spikes starts moving towards him. Don't wait for him to fly in the air then Finger, this increases the chance getting away with lesser HP than you could have.

When ganking 2 enemy heroes with allies, use the Impale+Finger on the one likely to die or has escape mechanisms like Clinkz/Anti-Mage. Sometimes the enemy's ally will try to help him. Voodoo him if he has spells to disrupt the killing. Ignore him if he has no stun. Take note of his position, leave the killing to your allies, animation cancel your attacks and move towards his ally. Once he starts to run, chase with blink dagger/force staff and Impale/Voodoo him.

In skirmishes, rush up to the prey with blink/force, then use Voodoo. Wait for your allies to catch up and stack stuns.

Before team clashes, don't appear in the enemy's team sight range, ever. You have blink/force, that's what they're for. You are not an initiator for such situations. And don't use Voodoo carelessly. It may be tempting to use it early but save it for the most dangerous hero.

When you get ganked, try to aim Impale to get multiple heroes. Use your disable on the hero who have not used his stun yet. TP or change Treads attribute if possible.

When you are getting damage from enemy heroes and waiting for Blink's 3 second cooldown to finish while juking, don't aim for which direction to blink to, you'll risk wasting time to get hit again. Keep clicking on the blink icon. You'll blink to the direction where you last picked up dagger. Same goes for Force, except that you'll fly to the direction you face.