Fullbuild example 1
Hi, I'm Adolebitque, a Brand OTP and according to LoLSkill (which is totally reliable, right?!) the #1 Brand. I ended my season (season 6 for the ones wondering) in challenger and I played probably around 80-70% of my games as support Brand.
On a serious note there may be people with a lot better Brand mechanics and people with a lot better game knowledge, but I'm sure you can pick up a thing or two if you're an aspiring Brand player.
Brand scales extremely well with flat magic penetration at all stages of the game. Brand's highest basic ability scaling is 0.6 points of damage per 1 point of ability power, so you'll end up getting exactly 1.5 times your ability power to your basic spell rotation (Q, W and E, W's 25% damage increase is unaccounted for but the point still stands), which is to say, is about 40 magic damage from your flat ap rune page that you might consider taking instead of the magic penetration page that I've suggested.
While 40 magic damage might seem pretty nice for a rotation damage increase, it's only notable at early levels, I'd say from 1 to 5, after which flat magic penetration will end up being more beneficial due to increasing your overall magic damage when Brand's base damage is very good (especially on his passive). If you are able to reduce the enemy magic resistance to 0, it will be very tough to itemize from that point on for the squishy champions who would awkwardly be forced to buy a huge amount of magic resistance to overcome your magic penetration.
Simply put, the game is rarely decided within the timespan where flat ap or mixed runes would be a little bit better, while flat ap will provide you a more solid impact in all other parts of the game.
Battle trance might be worse than Bounty hunter if you regularly get enough kills in your lane, but as your passive (should) keep you in "combat state", it's a no-brainer to take it over Double-edged sword. Though it should become harder and harder to consistently kill your lane opponents enough times to make Bounty Hunter more preferred as you rise in your rank.
Comparing deathfire touch and thunderlord's decree
Because of Brand's passive, deathfire touch applies to everything and the damage is from 25% to 100% of the damage deathfire normally does. From my personal testing and tweaking I had significantly harder time playing with Thunderlord's Decree, but I encourage you to test out for yourself - but keep a track of how well you do in games with respective masteries.
I should add that if you want TLD, you should want it exclusively for laning phase because after laning has ended, there is no question about the superiority of Deathfire touch on Brand.
Comparing Thunderlord to Deathfire on Brand is, to me, kind of like comparing flat ability power runes to flat magic penetration runes; you're sacrificing a moderately large amount of your mid-late game power for a little bit of early game power even though your early game is very powerful even as is. Having Thunderlord's decree won't save you in lane if you can't hit your spells for a full rotation, but you can pretty smoothly manage kills even with Deathfire touch's inferior early game damage. And to be honest, your laning isn't that much weaker with Deathfire Touch since it's pretty good for poking with your W.
And to be honest, if you hit your stuns in laning phase without missing spells before hitting a stun, you can play aggressive with either setup. Your passive does an amazing amount of damage as long as you manage to procc it. Not many botlane combos can out-duel Brand and a generic adc if you manage to get your combo and summoners off.
You will always want to pick spellthief as your support item, as Brand can easily keep proccing all the stacks without losing any effective gold by holding too long onto 3 stacks.
Generally, you want to keep at most 3 potions ready when you go to lane, but you can drop one or two in order to buy a Control Ward. Control ward is probably best put closer to your side of the bottom map so that you can contest it better if the enemy bot laners try to destroy it.
If you can afford it, it's usually a good idea to purchase Needlessly large rod before sightstone to give your early laning a bigger presence.
Since your runes do not grant you any magic resistance, abyssal scepter offers excellent survivability when paired with the Rylai's you bought earlier. The negative magic resistance aura is excellent choice to negate the possible magic resistance the enemy botlane support or jungle might've bought. Eye of the watchers is to get +1 ward and extra mana and cooldown reduction. You might want to finish Watcher's first, but that's up to you.
Depending on what you need, here are your most common options.
Liandry's is very nice due to its flat magic penetration which complements your already high penetration and counters whatever magic resistance the enemy squishies might buy in order to try and topple you. If you decide to buy Liandry's, your flat magic penetration will be around 50-60 when counting in abyssal sceptre, which will make you deal true damage against the enemy adc if he has no magic resistance from items.
Banshee's veil is for situations where you're being focused down (despite being support, yes, that happens) and need a few more seconds in fights to pull of the crucial stuns. It's especially useful if a dive deep -type of assassin is focusing you down because it prevents the assassin from instantly bursting you and gives you time to stun him so that your team can effectively kill him.
Void staff is a nice item, but its power falls short if the enemy has less than two to three players with extremely high magic resistance (120-150 would be a good threshold, I guess). Luden's Echo adds pretty nice burst to your already deadly combos, but the damage is unreliable in big fights where it'll procc on the first thing your spells hit.
Rabadon is absolutely niche and extremely expensive for what it offers with this build, but if you think the previous options are not for you and you have the gold, it's a decent amount of damage to your spells.
Pros / Cons
Absolute lane dominance against many matchups as long as you do not screw up. Against most combos you will come out ahead if you trade a spell for a spell every time the supports duke it out.
After level 6 there are only few support/adc combos that can out-fight a level 6 Brand and a random adc. The only way to properly dispatch Brand lane after level 6 is to kill Brand before he can do a single spell rotation.
Brand support offers a very good 2v3/2v2 potential as you can almost solo-kill an equal level opponent in the laning phase if you hit every spell, which means that as long as your adc hits an attack or two the poor soul who got stunned by you should be dead.
Brand support is similar to Zyra support, but Brand support offers more than just the initial big combo that Zyra can do with her ultimate; Brand still has a strong presence in fights even after using his own full combo.
If your lane is even, you will most of the times end up with more gold than the enemy support because realistically speaking not many supports can generate as much gold as a Brand constantly proccing his spellthief.
Your job in laning is to keep the enemy pair on their toes by taking control of the brush or dancing near the minion wave. You are extremely squishy, however, so you must not go too deep. You must also always avoid going too ham in lane, because if you miss a single spell in your rotation and ended up going too far, the enemy botlaners can crash onto you with no risk what so ever (before you have your ultimate, that is).
After level 6 you can throw your ultimate even if you don't think it's going to kill anybody. Keep in mind that it prefers champions over any other target so it's a good idea to wait until the enemy combo is stacked up. Because your ult slows enemies tagged by your passive, it's a good idea to hold onto your W until your ultimate has slown them down a notch.
And in laning, you can pretty consistently hit your pillars (W) by aiming at the time your enemy marksman tries to go for cs; either he loses cs and you lose a bit of mana or he takes a pillar to the face. If you see their adc or their support out of position, you can try to hit a carefully placed E -> Q or W -> Q combo and if it stuns, try to get your passive off. If the enemy support was not full hp or was not a tank, at this point you can often also ignite them and as long as your own marksman follows with it, their support should die even if they burn a flash, heal and an exhaust for it.
General match-ups: tanky supports
Namely champions like Alistar, Thresh, Leona and Braum. Out of these champions only Leona is really dangerous, and that's due to her E having very long range, being easy to hit and having a high amount of hard CC preventing any counter-actions from being taken.
Apart from Leona you can play pretty cocky on these lanes, chipping away the enemy adc with your spells. As long as you're careful of your positioning to not let the enemy support get to you without expending spells, you should be fine.
Thresh deserves a special mention; as long as you don't let him get to his E range of you, you should have no trouble dodging his Q or hiding behind your minions (Not adc!) to avoid being hooked by him. Bonus points if you ult someone who is taking Thresh lantern and the ult follows them for pin-ball action.
General match-ups: utility supports
Utility supports are champions that offer boosts to their adc in form healing, shields, steroids, etc, and fare rather poorly when isolated from their team. Out of utility supports you'll probably most often meet against you is Nami, Soraka, Janna and maybe Morgana.
The general consensus of these lanes is pretty common between all of them; levels 1-5 it's all about you poking with your W whenever you are just about full mana or have spellthief stacks to spend and punishing the enemy if they are out of position. These supports rarely have CC that is easy to land or is very useful, and even if they do hit you, in a 2v2 situation it's most often just a bad trade for you rather than you getting insta-killed. Don't try to out-sustain their mana pool if they have a reliable heal, but instead generate gold for yourself, create a little bit of pressure and if you land your stun, go in and go hard.
After level 6 you are the playmaker of the lane; the enemy botlane has two squishy targets and you have a devastating ultimate. If their bot is an immobile pair, don't hesitate to initiate with your ultimate when they are close to one another. It's pretty easy to hit your spells on fleeing enemies when you know they can't stick close to one another; they'll have much narrower path to walk on and if they dodge your Q (they shouldn't be able to without flashing though due to the slow from your ultimate), they will end up getting yet another bounce from your ultimate because you will (At least want to) aim your Q so that they can only dodge it by moving closer to the other teammate who was running away from the other in order to reduce your ultimate bounces.
When your ultimate is down it's all about generating gold and pressure once again, if you get a stun just go in and punish hard or get a kill. Avoid getting hit by their very telegraphed CC abilities, don't get owned by minions if you try to trade using auto-attacks.
General match-ups: mage supports
If you meet supports that would fall into this category, you're probably seeing Zyra. You could count Zilean as a mage support rather than utility, but he is a bit of a weirdo in the sense of being both half utility and half mage, so I won't say more about Zilean matchup than as long as you avoid his Q stun, you should come out on top. Remember that at level 6-15 your ultimate is shorter cooldown than his ultimate cooldown.
Let's assume that you're against Zyra, but this is pretty applicable on other supports as well that offer nothing or just about nothing else than damage and occasional CC. They will probably have less cooldown in their damage, they will probably have longer effective range on their kit and they will probably have more reliable form of CC than you. But what they do not have as much as you, is damage. In these lanes hitting even one stun that leads into your combo will almost certainly lead to a kill when your adc participates, while in return you're pretty safe against their 100-0 as long as you're prepared to retaliate when you get caught with decent reaction speed.
Your ult is the best ult out of damage supports in most scenarios and the ones that could trump yours require special scenarios that are simple to fix; vision. As long as you keep vision in control, you won't get randomly swooped into oblivion by a Zyra waiting in bush when you move as a stack of five players (Hi LCS!) to create joinder with Baron Nashor. But what you cannot realistically do is position yourself so that Brand ultimate combo would not disrupt the flow of a big team fight.
I'll try to summarize it so that it's a bit easier to understand if I was hazy earlier on;
Compared to other mage supports, Brand has the damage and he has a lot of it. You'll get poked more than you poke if the lane is even, so you have to either gain advantage by doing a hard trade or you and your adc play a bit more conservatively waiting for their mage support to go too deep in order to poke and then jump on him. Getting one combo off often means at least one kill in these lanes because the enemy counterparts are simply so cheesy with no defensive abilities to speak of.
Later into the game you, as a Brand, will have a larger impact than the enemy mage support as long as you avoid letting the enemy support to get a massive setup going, so vision is important. These lanes are probably the lanes that will end up generating the highest kill count in one direction or another. High gank potential junglers are extremely helpful on these lanes regardless of your situation, because ganks will very often lead to kills in these lanes and if you were behind when the jungler ganked you'll catch up while if you were ahead, your team's jungler will generate some more gold to snowball other lanes with.
In late game teamfights your job is to leave as big of an impact as possible. If your team is struggling with the enemy team's assasins, save your basic spells until they jump in and try to hinder them, but the moment you see the enemy team as a whole get a bit close to another, don't be afraid to throw in at least your ultimate and W. If you get a good ultimate and W off, it's very possible that the enemy team has to disperse in order to avoid collectively dying to your passive which opens up their team to a lot of vulnerabilities.
Remember; Your job is not to kill, it is to wreak as much havoc as possible (But also remember that you're still very squishy and should be extra careful about not positioning yourself too far and too deep).
About this guide
If this guide gains any traction I might edit it according to feedback and answer some possible questions. But for now, thanks for reading.