Prologue

You're here because you are playing Volibear or are interested in playing him, and you're looking for a build that will make people QQ. I'm here to supply you with that build.

Pros

+ Great solo top
+ Good lane partner
+ Awesome chaser
+ Great at tower diving
+ Amazing tank
+ Decent harrass (if you're up against melee)
+ Best execute in game imo
+ Best passive in game imo
+ Decent CC

Cons

- Very very slow
- Sustained dps (Until they're at 20% and then they die)
- Ult isn't very useful for this build
- Very susceptible to ganks
- Farming can be difficult (if you're up against ranged)

Reasoning for build

There are many ways to build Volibear. You could build him as AP and make his Sky Splitter and Stormbringer do decent damage, but the scalling on these skills is too low; 0.6 for Sky Splitter and 0.3 for Stormbringer. You could build him as an AD carry, but you're basically a less effective Olaf. You could even jungle with him, but I feel like he's a very slow jungler, and although his ganking ability is pretty awesome, there are faster and better junglers out there. In my opinion, the best way to build Volibear is to go high max HP as a main-tank or off-tank. My reasoning behind this is that all of Volibear's skills synergize very well with a large HP pool. Your passive will regen 1500+ HP, your Frenzy will be boosted to do 600+ dmg even before the execute part is calculated into it, and if your opponents don't surrender before you can get it, you'll gain 100 AD from your Atma's Impaler.

The Relentless Storm (Passive)
This is what makes Volibear so OP. It's almost gauranteed to get you first kill assuming the opposing lane isn't smart about it. Near the end of the game you'll be regening 1000+ HP before you die if it's not on cooldown. I've had this passive outheal a carry's damage and allowed me to kill them before the passive finished.

Thundering Smash (Q)
An awesome initiator. Great for chasing people down. Great for ganking. But it's easy to use this skill wrong. You never want to use it right away when ganking. The best use of this skill is when you see the enemy start to run away. You also never want to use it on the enemy's tank. When initiating a team fight, try to run past the tank and go for one of the squishy's. By doing this you'll have drawn the squishy into the range of a lot of your carries and given them an easy target to all jump on. Also, never use this skill when one of your teammates are running away with low health and you're in front of the enemy, you'll just fling them onto your teammate and kill them; try to wait till you're behind the enemy to ensure you save your teammate.

Frenzy (W)
The bread and butter of this build. This is what we call an execute; it does initial base damage, and increases the damage done based on the percentage of health the enemy is missing. Basically, the less health the enemy has, the more damage it will do. However, this execute also incorporates extra damage based on how much bonus health your Volibear has. The formula is basically (260 + Y) * 1.X)) where X is the percentage of health the enemy is missing and Y is the 15% from your bonus health. So if the enemy is missing 70% health and you have 3000 bonus health (which you will eventually), you'll do (260 + 450) * 1.7) = 1207 damage! That's a gauranteed kill on a squishy if they happen to be that low! Because it's an execute, you should always try to wait till an enemy is down to at least 30% health before you use it.

This skill is also amazing for harassing. Try to keep up your 3 stacks by attacking a minion every couple seconds, and when you see your opponent get close, smack em with a Frenzy and move away. The best part about this skill is the more you harass, the more damage you'll end up doing. And eventually, if you can get them low enough, you can pop your Ghost and your Thundering Smash and go in for the kill.

Sky Splitter (E)
Your AoE slow skill. Does a bit of a damage and slows them for 3 seconds. Has a small range on the AoE. Also fears minions for 3 seconds. Generally, you want to save this until you see champions trying to run away, or in a team fight when an enemy is chasing one of your teammates. Never use this skill just for extra damage. Can also be good if you're going for some harassment and there are a lot of enemy minions.

Stormbringer (Ultimate)
For this build, Volibear's Ultimate isn't as useful as in some other builds. It's still extra damage, but the damage it does won't turn the tide in a team fight. Still, it's extra damage and in a team fight it might just help kill them before they kill you.

Core

Heal OR Teleport
Depending on where you lane you will take either Heal or Teleport. You will take Teleport if you are solo top - ALWAYS have Teleport if you're solo top - you will take Heal if you're laning with someone.

Ghost
Great for chasing down enemies or running from enemies. As a tank it becomes more useful than Flash, since most times you'll be running from one side of the map to the other if a team fight goes badly. Definitely no question about this one.

Greater Seal of Endurance
Adds %0.5 of your max health as health. Nine of these will give you %4.5 more health. When you already have around 5k health, this will give you more health than flat HP runes. If you wanted, you could sub in Greater Seal of Health for a better early game or Greater Seal of Armor for more armor, but this will give you a bigger HP pool late game, thus more damage with Frenzy .

Greater Mark of Attack Speed
This works well for getting your 3 stacks of Frenzy up ASAP. Also synergizes well with your Ult, even though it's not as useful with this build. Lastly, if you manage to get your Atma's, this combined with your Frenzy 's passive will give you that needed attack speed to make your melee pretty devastating. You can also sub in Greater Mark of Desolation if you don't have Alacrity.

Greater Glyph of Scaling Magic Resist
Straight forward. You can use Greater Glyph of Magic Resist also but this is better for late game.

Greater Quintessence of Endurance
With these, Greater Seal of Endurance, and Juggernaut from the defense tree, you'll be gaining %12 of your max health as additional health. That's around 600 more health once the build is done.

Kinda obvious. You're a tank, so why wouldn't you go down the Defence tree. Most benefit here, especially from Juggernaut . Leftover points go into Offense just because there's more benefit.

Your optional items will be dependent on your role. Are you the off tank or the main tank? If you are the main tank you will be getting more tank items. If you are the off tank you'll be getting more dps items.

Core Items

The reason these are your core items is because they will never change. You'll always get these items unless there is a special case. ALWAYS ALWAYS ALWAYS start with Doran's Shield. This will give you too many benefits in the lane phase to pass up; health, armor, regen, and best of all a nice boost to your Frenzy . Before your first recall, try to get enough gold for a Heart of Gold and Boots. Your boots will either build into Mercury's Treads or Ninja Tabi, depending on if the other team has a lot of CC and AP or more AD. After your boots, start working towards a Warmog's Armor. Warmog's will give you a huge boost to your Frenzy . Suddenly your Frenzy will be KOing squishy champs when they're at a third of their health. If you are main-tanking, you should wait to get Atma's Impaler, but if you're off-tanking, you should get Atma's right after Warmog's. This will give you a nice dmg and crit buff to your melee. Your last item in both builds should be Frozen Mallet, which will help you to secure kills and give you more health.

Off-tank

After Atma's, you should build Maw of Malmortius. This recently added item is very nice for off-tanks, as it gives you some MR plus a shield that could safe your life, while still giving you AD that is comparable to a BF item. Now that you are semi-tanky, we can focus on a pure DPS item. Grab a Black Cleaver. Although there are items with more AD, this one gives you ASPD, and you'll help yourself and your AD carry by getting rid of 45 AR from whoever it is you're focusing. Finish off with Frozen Mallet, and you're a force to be reckoned with.

Main-tank

When building main-tank, there are many situations that may call for a different type of AR or MR item. For instance, Randuin's Omen is a good all around AR item, but if you're facing someone like Tryndamere or Master Yi, you might want to go for a Thornmail instead. Or if there's an ASPD champ like Kog'Maw or Teemo, you might want to get Frozen Heart. If you find you're being ignored in team fights, you could also get a Sunfire Aegis. Lastly, if you're on a roll and think you'll be dominating, you could get a Leviathan early on and skip out on the Frozen Mallet, which will truly make you invincible.

Same goes for MR. Banshee's Veil is a good default, especially since it gives you health, and extremely important against combo champs like Annie or Brand. But if you're up against champs that have low CD skills like Kennen or Dr. Mundo, or more linear damage like Cassiopeia, Swain or Ryze, you should get Force of Nature instead. Guardian Angel is just a good troll item if you're already dominating.

This may be my first guide, but please please please read the whole thing and test out the build before you rate it. If you give criticism, please try to give constructive criticism, and not just, "You suck lololol." Let me know if I have made any mistakes, or if you have some suggestions for improvements.

Thank you for reading and I hope you have much success with my build!