The majority of Huskar guides seem to rely on Burning Spears as a main component. This is the wrong way to play him. Damage over time can be great for harassing, but an unstoppable beast is great for killing. Lifesteal Huskar is an unstoppable beast. With Beserker Blood you become very dangerous to kill. (It stacks 13 times before you die, at max level that is 156% more attack speed and 104 more damage). It should be easy to see why Lifesteal Huskar is difficult to kill. The closer he is to dead, the faster he regains health and kills his enemies.
The items seem a little confusing in this build so I'll walk you through it. At the start of the game don't buy anything. Don't worry. You can cast inner vitality to heal and be able to buy your first item within 2 or 3 minutes. You want to buy a mordbid mask. As long as you aren't laning against two high spell damage character DO NOT BE AFRAID TO HARASS. Play it smart though, don't overextend, don't tower dive. Just win lane. I suggest laning with someone who can slow. (Tidehunter, Crystal Maiden, Veno, etc). Don't be to afraid to tank some creepwaves or take some harass. You have to remember when you're playing Huskar you're most powerful when you're close to death. It makes playing him a thrill.
(These builds can change if you're jungling or laning/roaming, I will explain in a later chapter).
Next you want to get Power Treads (set them to strength, you need all the health you can get). Realistically if you're laning/roaming you can look at getting your boots and Helm of Dominator in 8-12 minutes. A great early build. Save you cash up after buying these until the 20 minute mark unless you can make an educated guess of how the game will play out for you. Once you have Beserkers Blood level 4 you can take Roshan as long as you don't get stun locked (it happens). To prevent this you can use your Helm on a creep and tank Roshan until you have a fair amount of Beserkers Blood and let the the creep tank Roshan for the rest of the fight.
At 20 minutes you have to consider how your game is going. If you are dominating the game feel free to rush a Satanic. It will heal you fully in a tough time. (In a game you can manage to get Satanic you can usually go heart after but BKB or Daedalus is a good choice). If you're struggling I'd suggest considering why. Is the other team to tanky? Get a crystalis. Are you getting stunned/nuked to death? Get a BKB.
For Luxuries I'd suggest Satanic and Heart as the two to strive for followed by Daedalus. If you already have a Crystalis and a BKB going Daedalus over heart isn't a bad idea.
The skill build is pretty self explanatory. It's built to keep you alive and strong. Max your E, followed by Q, and you ultimate whenever it's available. Stats are more important than Burning Spears. Take it last over everything.
The only upside to burning is spears is that it's manual cast range is farther than Huskars auto attack but the use for an extra long shot seems irrelevant to me. Lifesteal is a much more powerful orb effect on Huskar.
You want to always be in the lane with the your teams Jungle (regardless if you're using it or not). Ask yourself these questions to decide where you're going to farm.
Can my partner solo lane?
If no, stick around. If yes, you could take the jungle.
Is someone in the jungle already?
If no, feel free to seize it. If yes, leave it to them. You can be more deadly in lane anyway.
Do I want to end it early?
If no, feel free to jungle. If yes, roam the map like a madman.
Jungling Huskar can be scary. DO NOT JUNGLE IF THE OTHER TEAM HAS A BLOODSEEKER. HE WILL FIND YOU. AND KILL YOU.. To do it I prefer to have 3 into Beserkers Blood and my morbid mask. At this point you can take on the ancient creeps (the dragons can give you a run for your money though). You can start with 2 in your Beserkers Blood but it's scary because Huskar will float around 60-120 health the whole fight and it can make you uneasy.
Laning Huskar is fun. Don't fear Harassment. Just Harass back. You're going to become stronger than your enemy the more they attack you. The tides of battle will switch swiftly. You should lane until you can take Roshan for the first time (level 7-10). Afterwards roam and help your team gank and since you're a carry feel free to take the kills. You want to get huge.
This is a picture of the results of a laning Huskar captains mode game:This is a picture of a farming Huskar in a bot match game:
As said before you want to work with anyone with a slow or a decent stun. This section is for special mention and enemies
Dazzle Shallow Grave is deadly on Huskar
Lina Inverse - Watch out for Laguna Blade when you're low health
Demon Witch - Watch out for Finger of Death when you're low health
Necrolyte - Watch out for Reapers Scythe when you're low health
Bloodseeker - Watch out for his ability to track you and gank you when you're low health
The solution to 3/4 of these problems is a BKB.
Thanks for reading, hope this helps. Hope it turned out well. First guide I've ever made. Feel free to leave comments, criticism and stories of how it went for you.