I'm Sp12 -- I write guides here and can be found streaming at http://www.hitbox.tv/sp12; if you have any questions/comments feel free to post at either.
This is a set of guides for Faceless Void. I am a carry player, and Void is one of those gamebreaking ones with a special penchant for AoE teams and for locking down a pesky enemy carry (Naix, Sven, AM).
Each build gets it's own minisection for you to check out, so consider this an anti-alt-tab guide. They are sourced from the various Dota scenes, the depths of the playdota discussion forum, and my personal experience. The formatting for this guide is borrowed heavily from my Spectre guide, which you can check out for some alternate playstyles for Spectre if you play her.
Void is one of the more versatile and outright hardest carries in the game, but with strong early presence via sphere. He has some of the best scaling steroid skills, and has absurd lane presence for a melee carry. After a bit of babysitting, he can often be left alone (with the threat of a chronosphere forcing the longlaner out) with a tp scroll to farm, then tp in to defend with a sphere. He is increasingly popular as the metagame shifts to shorter and shorter games. An Anti-Mage with treads and level 6 can contribute nothing but a killsteal to a fight or gank. A Void can a chronosphere and decent damage.
As a hero Void has a few areas that need focusing -- mana issues, stacking attack speed for Time Lock, and making sure he's able to perform/survive both in and out of sphere, often through a combination of HP items and BKB.
Void is somewhat durable (backtrack, 5 starting armor, blink), a strong teamfighter with an awesome BKB penetrating ulti, and a great laner. He has pretty strong initiation in the form of Time Walk, which helps secure early kills and makes him more difficult to gank. Time Lock is a lot of what makes void so scary lategame, as it's a BKB penetrating disable with no cooldown, limited only by attack speed. Even with only moderate attack speed from treads and levels you can consistently keep your target disabled ~half the time. Against an enemy carry with maybe only 5 seconds with BKB to get work done this is debilitating, as it consistently cuts their DPS in half while giving your team room to kite them. Backtrack gives void some chance-based durability, with a 25% chance to dodge spell damage or physical damage. This skill is not that good early but obviously scales perfectly as you gain HP and your opponents gain damage. Chronosphere is one of those gamebreaking ultimates like Black Hole, but only has a 80s cooldown.
Note that for time calculations this guide assumes around ~350 gold per minute. Early less is expected and later more, but this will help you identify the time constraints you're under for certain builds without having to run them multiple times. Void can run somewhat like antimage, blinking between camps and farming with battlefury, and he tends to snowball lategame so expect far more than 350 gpm past 20 minutes.
Then don't use it. Faceless void has one of the most variable competitively tested skillbuilds. I will suggest that if you're not completely dominating both your lane and the lane your enemy team's ganker is in, you should probably max time walk. The extra range and sometimes the cooldown reduction and extra slow are significant. On the other hand, if you're against a solo offlaner maxing time lock at 7 will set you up for an easy sphere kill and then continuing lane dominance.
In your typical pub dual vs. dual I will suggest grabbing two levels of time walk by 3, and at least one time lock and one backtrack as the first point gives you a full 10% chance. I prioritize time lock since the double damage in sphere buff means it gives you some real kill potential early. If your lane really stinks you might have to max backtrack at 7 with no points in time lock.
For less standard matchups,
Offensive trilane? Split between time lock and backtrack with at least two in walk, more backtrack if you're losing the lane and time lock if you're winning.
Defensive trilane? Max backtrack with two in walk.
Solo vs solo safelane? Max time lock.
Dual vs. dual safelane? Split between time lock and backtrack with at least two in walk.
Solo/dual offlane? Time walk and backtrack.
Likewise, the item build isn't set in stone. If you're getting total freefarm in lane you can skip finishing the poor man's shield and grab a midas. If you have an Omniknight or Dark Seer maybe you can skip BKB or consider Mask of Madness more seriously. Maybe you started with an armlet build but need to finish a battlefury at some point for a Phantom Lancer.
I'm not going to list out skills/whatnot, there's a lot of excellent videos and replays of how to play Void. An easy way to get better is to watch replays on player perspective -- filter recent games for Void and very high skill level. I will cover some of the points I don't see people execute consistently, even at higher levels.
Mask of Madness is a very risky item. If it works for you get it.
Much like Midas, you should never go into a game with a plan to get Mask of Madness. If the enemy team picks no ranged DPS and few stuns then you can start thinking about it. If you start to snowball you can think about it.
I will post a link to one of my friend's very well-read (if a bit pubby) void guides, which has some math (~halfway through guide, MoM vs. maelstrom comparison) as to why Mask of Madness is outclassed by Maelstrom for both DPS and survivability, but don't let that stop you from getting it if you like it, it will give your more bashes if less DPS and EHP. In fact, if you're in sphere it will almost equal the DPS from Maelstrom since bashes do double damage in sphere. The movespeed and extra chance for bashes is good for jungling/chasing. Not a bad item, but not one I can blindly recommend. It has good synergy with Maelstrom as well for increasing your lightning AoE damage.
If you catch five in a sphere and battlefury everyone down with the +100 attack speed it's obviously a fantastic choice. If you catch 3, get stunned, then focus fired as sphere ends it's bad. It is good if the laning stage is going on too long as you can reliably catch both laners in a sphere then solo kill or choose to end your laning stage by transitioning to jungle. Certainly something to consider, but not something for every game.
That said, if you're playing for a mid-game void I urge you to read ahead to the second build.
This build is very safe if a bit boring, and does require your team make space for you to farm. Fast poor man's shield into RoH makes you survivable early while the eventual battlefury solves your mana issues. Your DPS comes from the extensions you buy from your fast farming and split pushing from battlefury, though don't discount Bfury alone as a DPS item.
The PMS and RoH should solidify your laning stage, and you basically play the hard carry by sitting in lane afk farming for your battlefury. You should grab a tp scroll around the first night to either blink tp avoid a gank or to tp in to participate in a fight.
Void is one of those heroes that can keep going for as long as the game goes, so keep farming. The defensive extensions listed are probably the best to grab first, as they add not only offensive but defensive power. BKB allows you to be productive even if you don't catch everyone in sphere while adding some HP/damage, while butterfly stacks with backtrack to give you a ~51% dodge chance vs. physical attacks and good DPS and attack speed. Scepter is more controversial, but it's increasingly popular and lets you use sphere liberally for solo kills, plus it adds ~400 HP and some stats. AC is like a more team oriented butterfly. Manta gives general stats, movespeed, and the split to clear disables and add confusion/push. Halberd is an alternative to butterfly that adds extra bulk and a powerful active.
Once you're not at major risk of dying grab luxury DPS items and the like.
Mask of Madness is covered above.
Midas can be had early on any of these builds, and it's a good item for void as it's +30 attack speed for your bash.
Vanguard is a bit of an outdated option -- if you're considering it I recommend the second build. Alternatively, just grab an early point booster for an eventual scepter.
MKB is a good item, but I'd rather get a more defensive extension like any of the three in core first. It's obviously very important against evasion.
This build is still pretty safe but more active early, and is increasingly popular against teams that want to fight from 15-25 minutes as Voids recent buffs give you threatening DPS so no one actually wants to fight your void. I think it's my favorite. Your team still has to make room for you, but after MoM you can burst down solo heroes and snowball. I often go this build when there's an invoker, sand king, or other ranged damage source to work early with sphere.
If you can get a midas, do so. If not, maelstrom and MoM are still a pretty good farming items and some of the best DPS ones.
This build prioritizes playing actively with your team, as sphere is one of those top-tier teamfight ulti. Think of this as a modern mask of madness build. Early activity, but still good at farming and with EHP.
Play safe, grab your farm, bully people with your base stats.
MoM lets you jungle in between sphere cooldowns. Use sphere liberally to kill solo heroes.
Void is one of those heroes that can keep going for as long as the game goes, so keep farming. You have pretty easy extension into Mjollnir
This build is pretty funky but still effective. It was semi popular in the SEA scene about 3 months ago. Your team still has to make room for you, but not much before you can start making room for them. Fast poor man's shield into HoIW makes you survivable early while extending into your core. The necrounits, HoTD creep, and Manta illusions all work in sphere and help push pretty hard. This is another one of those builds that tries to be useful early, and is really good if you get counterpicked by AoE disables/damage or BKB-penetrating disables like roar.
The PMS and HoIW should solidify your laning stage, and you play more of the midgame carry role ala PA/Jugg. Necronomicon in sphere will, if not killing your target, burn all their mana making them unable to respond adequately after sphere wears off. This is especially good vs. initiators like tide that want to walk in and force a fight. Necronomicon also has non-zero stats, and the warrior deters AoE disables/nukes from being tossed in the sphere. Time lock provides some additional lockdown for your necrounits to do work. You can dominate the centaur khan for an easy followup stun after sphere.
Necro 3 falls off a bit later, but manta keeps going. AC provides armor and attack speed for your units and amplifies their damage in sphere, while also helping make time lock more reliable. As needed you can build towards typical hard carry items.
A very popular current option for Void given his huge buffs.
How do you zone a blinking 600+HP 5 armor backtracking melee hero with a PMS? What do you do about him killing your cores with a MoM?
Spheres cooldown drops, but its importance rises. Start thinking more cautiously about using it for casual kills on noncores.
A lot of your friends are foes if they're on the other team. A strong laning phase and other teamfight ultimates is one of the best ways to maximize Void's advantages. On the other hand, if your laning phase goes poorly or the enemy team has good teamfight ultis it can limit your options come midgame.
Special mention to Disruptor, Witch Doctor, Jakiro, Crystal Maiden, Shadow Shaman, and Lich as great supports that can lane with you then later synergize with your ulti.
Dark Seer and Magnus give an easy va***m setup for your sphere.
If they're on the other team they can make your laning phase an issue or limit the options in your sphere.
Invoker, KoTL, Queen of Pain, Sand King, Ancient Apparition, Jakiro, Undying, and Venomancer all love the disable your sphere provides to do early magic damage. These are all heroes on the enemy team that should tell you BKB is probably required and Mask of Madness is a no go.
Tidehunter, Vengeful Spirit, Beastmaster, Shadow Demon, Pugna, and Omniknight (among others) all have good spells to counter your damage output in sphere (making the necrovoid build more attractive). Venge and BM both have BKB penetrating disables to prevent you from doing damage, and BM's boar will make you very easily kited. Venge can also choose to swap a friend out instead of you.
So there's some playstyles/builds/advice for Void. If you have any questions/comments/criticisms/conundrums feel free to post them. If you're still doubting the lack of Mask of Madness I urge you to read the link posted. If you feel it was worth the read a vote up helps get builds seen more.