Volibear is a Tank, Fighter, Jungler, Melee champion. I will play Volibear as a Melee Fighter.

Berserker's Greaves
This is the boots that i will choose almost every game.

Warmog's Armor
This item, is the item that Volibear 100% needed. You should build this ASAP

Wriggle's Lantern
This item is good for you in the early game if you are jungle. That's because it gave you Life Stealth, Armor and you can ward anywhere every 3minute. And you should!, cause you are a jungler~ :D

Infinity Edge
This item can give u huge of damage

Trinity Force
This is a balance stat item. You can got att speed, health, att damage, mana, ability power from it.

Bloodthirster
This item is the best life stealth item in league of legends. I will take bloothister when I am against a balance team.

Thornmail
I will choose Thornmail to against ad carry team

The Relentless Storm - When Volibear's health drops below 30% of his maximum health, he will health for 30% of his maximum health ocer the next 6 second. This passive effect has a 120 second cooldown

Thundering Smash
For the next 4 seconds, Volibear will gain 45% movement speed if he is moving towards a nearby visible enemy champion. Additionally, Volibear's next autoattack during this time will deal 25 / 50 / 75 / 100 / 125 bonus physical damage and will fling the target behind him.

Frenzy
Passive: Volibear temporarily gains 8 / 11 / 14 / 17 / 20 % bonus attack speed after an autoattack. This bonus stacks up to 3 times and lasts for 4 seconds.

Active: While Volibear has 3 stacks of Frenzy, he can activate this ability to bite a target enemy. The stacks won't be consumed. The bite will deal 80 / 125 / 170 / 215 / 260 (+18% of bonus health) physical damage. This damage will in turn be increased by 1% for every 1 % of the target's missing health.

Sky Splitter
Volibear lets out a powerful roar that deals 60 / 95 / 130 / 165 / 200 (+60% of ability power) magic damage and slows nearby enemies by 30 / 35 / 40 / 45 / 50 % for 3 seconds. Minions, monsters and pets are feared for the duration as well.

Stormbringer
For the next 12 seconds, Volibear's autoattacks will blast his target with lightning that will bounce to up to 3 nearby enemies. Each bolt of lightning will deal 75 / 115 / 155 (+30% of ability power) magic damage and will only hit each target once.

I take 1 Thundering Smash at level 1 to knock back enemy and max it last.
Frenzy Give me enough damage to kill enemy, always take Frenzy and level 2 and max it by level 9
Sky Splitter can slow enemy and because of that I take Sky Splitter at level 4 and max it by level 13
Always up Tunder Claws at level 6,11 and 16

Heal
This is good for volibear when he is low health
Passive + Heal = Useful

The reason that I choose Ghost is to let me chase Enemy easily. You can use Sky Splitter to slow down enemy and Ghost + Thundering Smash to chase your enemy who try to run away from you.