Some thoughts on Outworld Devourer mid, from the perspective of having to deal with him:
He's a very popular mid choice, and rightly so. He's exceptionally strong in a 1 v 1 laning situation due to astral imprisonment. The intelligence theft from astral imprisonment makes it easier for him to last hit, and since many of the commonly played mid heroes (QoP, Puck, Storm Spirit, Batrider, and in pubs Lina, Zeus, Tinker, Skywrath Mage, Invoker, Death Prophet) are intelligence heroes, he hampers their last hitting ability whilst making them unable to use their spells that they often rely upon to farm. He also shuts down other popular mid choices like Magnus and Timbersaw who have limited mana pools, yet rely on spells to help them farm and control the lane.
The obvious solution to this is to take a hero that is not particularly mana dependent (and are not intelligence heroes so he can't ruin their last hitting power), accept that you will never have any mana, and just focus on either last hitting, or health trading him out of the lane by harassment backed with additional regen. Good options here are Kunkka, who is tough and difficult for OD to burst down, and can farm and harass HARD with tidebringer which is mana independent, Dragon Knight who is never going to get killed by OD, and Brewmaster. From the agility pool, interesting options are probably Drow and Sniper, who don't need mana to get their farm, but are susceptible to quick deaths to OD's burst damage. Better options are Troll Warlord, who may be easily able to harass him out of lane, Viper, who doesn't really have any spells anyway, and is quite tough, and the quintessential counter pick, Razor.
The reason Razor is such a hard counter to OD is Static Link. This spell has an essentially negligible mana cost (50 at level 4) and essentially turns the tables on OD, as stealing his damage prevents him from last hitting, keeps you alive and allows excellent harassment. Just to add to the fun, it stays active during astral imprisonment, so there's no escape from the damage slurp.
Another route to take perhaps is to lane against OD using a character that is farm independent and just needs levels, e.g. Pudge, Nyx Assassin. You won't be getting much farm, but as long as you stay safe, try to pick up what you can and get to level 6/7, you can then move into the phase of the game where you want to shine using your ganking abilities.
A final interesting point: I had what I thought was the misfortune of having to lane mid against and OD using Lion. I thought it was going to be a very rough matchup, as Lion is an INT hero, but (partly because the OD player wasn't great) it actually turned out really well due to Mana Drain, lion's much maligned 3rd skill. After being astral imprisoned, I was able to recover mana I spent from OD, which meant that although my mana pool and mana regen rates were low, I had an alternative source. At level 6, Finger of Death could blow up OD easily, and I went on to win the lane, and carry the team to victory, I just had to be very careful with my mana pool. It may not be the best option, but it turned out to be far from the worst.
Some thoughts about boots:
Boots are arguably some of the most important items in the game, especially since pretty much everyone will be carrying a pair for the entire game (the only real exception that comes to mind is a maxed out late game weaver, who uses shukuchi for movement, and drops the boots for a 6th slot damage item). They are the best and most cost efficient way for any character to increase their movement speed, and can really make the difference in a fight, particularly in the early game.
There are 6 different boot options:
Boots of Speed (brown boots, boots)
Phase Boots (Phase)
Power treads (Treads)
Arcane boots (Arcs)
Tranquil Boots (Tranqs)
Bots of Travel (BoTs)
All of which build from Boots of Speed (+50 MS, 450 gold)
Phase: Assembled from boots, and two blades of attack (450+450+450 = 1350), give 55 additional movement speed (MS) and +24 damage), as well as an active MS boost (16% for 4 secs) combined with a phase effect allowing you to walk through other units (low cooldown of 8 secs, spammable). Not disassembleable.
Treads: Assembled from boots (450), gloves of haste (500) and (little known fact according to the wiki) either a belt of giant strength, band of elvenskin or robe of the magi (all 450, total 1400). This component decides the initial stat bonus. Gives 55 MS, +30% attack speed and +8 to the attribute of your choice, with the active effect switching between STR, AGI and INT. Not disassemblable
Arcs: Assembled from boots and an energy booster (450 + 1000 = 1450). +60 MS and +250 mana, with an active mana regen effect (cost 25 mana), giving 135 mana to everyone around you, on a cooldown of 55 secs. Disassemblable
Tranqs: Assembled from boots, a ring of regen and a ring of protection (450 + 175 + 350 = 975). +75 MS, +3 HP regeneration, +3 armour. Active heal of 250 hp over 20 secs for 25 mana on a 60 sec cooldown. Have the ability to break, and leave you without the heal effect and stuck at only +25 MS if you take 3 instances of damage in ten seconds, and the total damage is more than 20. Disassemblable
BoTs: Assembled from boots and a recipe (450 + 2000). +100 MS and active teleport to allied creep or structure every 60s for 75 mana. Not disasemblable
Most people pick up boots as their first purchase, and more often than not, will upgrade them as their first major investment. Generally this is good advice in most situations, but a key thing to think about is how purchasing boots affects your role,particularly in the role of a poor, cash strapped support. Do you REALLY need boots? - Yes, definitely, but do you need them NOW? As a support I've often found myself after buying the courier, the first set of observer wards at the start of the game, and upping the courier, starting to maybe have enough gold for boots at around 6 mins or so. Inconveniently, this is also around the time the first set of observer wards will need to be replaced. - Often, you may be better off sucking it up for another minute or two, wait for your boots and make sure the wards are replaced immediately. It is also very dependent upon what character you're playing - Supports like KotL, Abaddon and Naga have high starting base MS and can get away without buying boots (or upgrading them) a little longer, on the other hand, Crystal Maiden and Shadow Shaman are slow as shit, and not having boots may increase the chance of missing a first blood or getting first blooded. To put this into perspective, Naga without any boots (320) is almost as fast as CM with normal boots (330).
Addtionally, other roles will generally want boots, particularly roaming gankers, but if you're a safe lane hard carry who's going to be farming constantly for a while, like AM, Spectre, PA, PL, do you actually need boots right away? I'm not suggesting you don't buy them, but maybe you're better off at first putting 300 gold into a poor man's shield, giving you extra protection against harass so you can stay in the lane, some additional last hitting power to make your farming easier, and a little more attack speed, particularly if your team has been protecting you, and you have an ability to improve your mobility anyway (blink, pseudoblink, invis, spectral dagger). You may want to spend a little money bringing a salve to you on the courier in order to heal up and stay in lane farming etc. Getting hurt, having to walk back to the fountain without boots just to heal up isn't worth the XP and last hits missed if you can help it, and having boots doesn't make it much faster. It's cheaper and more efficient to get a salve brought to you on the courier than it is to buy a TP at the side shop, TP back, heal then walk back to lane. Getting more regen after the start isn't an ideal use of your gold, but it's nothing to be embarrassed about. No one sensible will bite your head off for it, especially if you're having a rough laning phase. It can even lead to effective health trading, where you can heal up, harass your opponents out of lane and get free farm while they miss out on last hits and XP.
So, the next stage, choosing what boots to upgrade to.
Firstly: Do you definitely need to upgrade your boots? Again, as a support, you may need to prioritise wards and things like dust over improved boots. Typically you may want arc boots to use more spells, but perhaps you just need to manage your mana pool more carefully? As a carry, do you actually need to improve your boots right away? Are you better off saving for a crucial item to help you farm (i.e. a battlefury for AM, PA, or a vanguard for some other heroes to keep them alive in lane, such as old fashioned vanguard -> radiance builds on spectre) or a critical item such as an orchid for clinkz or storm spirit which allows you to actually perform your role properly?
But, back to choosing the correct boots: This is where a little more of my opinion comes in.
Let's deal with BoTs first: Basically, they're a late game item on almost everyone except split pushers, and even then, they're not normally a fist choice of boots, except in the case of tinker. They're generally bought up in the late midgame to lategame for split pushers, or as a desperation measure in very tight games in order to attempt to outmanoeuvre the opposing team and break their base before they can react. They're expensive, the components aren't easy to build up. Situationally they can be really good on some of the slower heroes, invoker in particular can really use them to his advantage both from the natural MS and to help his split pushing.
Tranqs: Basically, I think these are generally shit. Although these are dirt cheap and an easy build up, they're the only boots (except BoTs?) where not all the components can be bought from the side shop, meaning that you have to use the courier to get the ring of protection (when it could generally be used more importantly elsewhere) or you need to start with a ring of protection, which isn't always ideal use of your starting gold. The MS is great, and can particularly help slow characters like CM, but is prone to breaking at the worst possible moments, like, say when you're desperately attempting to flee... You also have to remember that you're giving up the other benefits of other boots when you chose these. Generally I don't think these are a good choice for anyone, especially after maybe 15-20 minutes. I think they're situationally useful in 4 cases:
- If you are a hard carry farmer: These essentially give you a free salve every minute, a bit of armour and some health regen, which should keep you in lane and farming passively. They should always be upgraded to actually useful boots ASAP before you start to engage in teamfights.
- If you are a roaming ganker, particularly a slow one. If you are going to need to be moving around the map a lot on foot in the early game (e.g. a character like Pudge, a roaming Venge) then the significant MS boost available when not under attack can be really useful. Similarly, you can make your kill, use the active to heal up, then go roaming again for another target. Probably still need upgrading before teamfighting starts in earnest.
- You are going to be building a Mekanism or Pipe (and also want the ring of protection for a Ring of Basilius or something to help pushing/making a Vladamir's offering). You can use the Ring of Regen in these cases after disassembling the boots to get a little head start on the Headdress for Mek or the Hood of Defiance for Pipe. You're still going to be wanting to disassemble these boots after 15 minutes.
- You want to use a soul ring/tranqs combo to keep boosting your mana and regenerating the sacrificed HP. Generally I find the HP loss from the soul ring to be more than manageable without needing the Tranqs, especially as the Soul Ring contains it's own ring of Regen.
I tend to find support characters are either alive, or dead, rather than walking around on mid or low HP, meaning the active heal isn't very useful for me.
Arcs: These are quite expensive, and the 1000 gold for the energy booster is actually quite a lot to save, especially for a poor support, making the build up fairly difficult. Again, you're sacrificing the damage and benefits of the other options, notably treads and phase, for a mana pool boost and a active effect. While there are characters that undoubtedly need these or strongly benefit from them (Shadow Shaman, Sand King), they're very much a situational pickup at best for most heroes, even the mana starved ones. Heroes on a tight mana pool (e.g. Sven) are often much better off with a soul ring, which is cheap and easy to build up, as well as having a lower cool down. These boots are useful to have in a team, and are especially good in the early game when people are running about with tiny mana pools and maxed out expensive spells (most people normally max an ability by lvl 7) but have very little effect late game. Probably solid in a trilane. Some utility if you want to disassemble later to make a bloodstone.
Phase: Easy build up, quite cheap, good damage early in the game, active effect strong all game, but particularly in the mid game for ganking and chasing. Generally useful on heroes that want to stack straight damage (such as PA) or really want the escapability or chase effect (they're an interesting choice on a more fighty windrunner, as they give extra damage and the active synergises well with windrun). Often built highly effectively on heroes such as doom and lifestealer as part of a 'racecar' build of Phase, drum of endurance, yasha in which MS is prised over all for the ability to run down fleeing opponents. Lifestealer can use them to catch people with open wounds to get up to them, Doom just becomes terrifying, as Scorched Earth also increases his movement speed. Damage is a tradeoff compared to treads. +24 damage vs the +8 treads can give you if you put it on your primary attribute is a lot more in the early game, but in the late game, the extra attack speed from treads becomes more and more powerful.
Treads: Easily my favourite boots, and I build them on almost everyone now. The build up is really easy, and you can take the belt of giant strength early to give you a little more survivability when you're completing them in lane. The attack speed is great, and really scales well into the late game, particularly on damage dealing right click characters. It can also help people with shitty attack animations like CM. The +8 to the attribute of your choice is brilliant. Supports really like the +8 to strength (it's almost as much as holding an ogre club, and more than a bracer), as it stops you being so squishy, people with mana problems can get a bit out of the +8 intelligence, as it can make the difference between getting off one more crucial spell in a fight. Everyone can use the ability to toggle to +8 strength for HP when running away on low health. Agility carries obviously like the +8 agi for damage and attack speed. Everyone can use their natural stat type for extra damage. Anyone using a bottle can switch to agility before glugging, minimising their HP and Mana, getting more out of the bottle's regen, and this also works with salves, clarities etc. They're flexible, and awesome, and IMO almost always the right choice no matter what.
