The strength of Kog'Maw is his ability to kill opposing Champions on extreme long range.
His Bio-Arcane Barrage and his Living Artillery is his option to success.

Bio-Arcane Barrage scales with Ability power. The best way to keep your damage output high is to built for a hybrid item built.

In the next steps I show you how to play a successful carry hybrid Kog'Maw.

It's my first Guide so keep restrained about my judgment.

I take,

• 9x ( Greater Mark of Magic Penetration)
• 4x ( Greater Seal of Replenishment)
• 5x ( Greater Seal of Attack Speed)
• 6x ( Greater Glyph of Scaling Ability Power)
• 3x ( Greater Glyph of Cooldown Reduction)
• 2x ( Greater Quintessence of Movement Speed)
• 1x ( Greater Quintessence of Magic Penetration)

Magic penetration works with each of Kog'maws abilities and allows him to deal high damage with his Bio-Arcane Barrage.

Mana regeneration isn't that much needed, but is really useful to keep laning longtime until reach Level 6 or staying some time in longer team fights and to keep your wasted mana of Living Artillery stacks in normal dimensions.

Attack speed is useful to deal more damage with you Bio-Arcane Barrage. This built has a really slow early game and you gain attack speed with leveling Caustic Spittle. To get more damage output in early game its really useful. And gives you a close attack speed next too 2,5 Attacks per Second.

Ability power Glyphs per Level to keep ability damage in accordance with your Level.

Cooldownreduction Glyphs for Living Artillery and Bio-Arcane Barrage", to keep the cool down of Bio-Arcane Barrage close to the duration of itself.

Move speed Quintessence to keep in range with Living Artillery and Bio-Arcane Barrage.

First i start with Boots. It keeps you adaptable and makes farming more easy. Its good to avoid unnecessary damage too.

3x Health Potion to stay long time on lane until reaching enough gold to buy Recurve Bow. Don’t forget to buy Recurve Bow as fast as you can to be more efficient in early game!

If you not possible to get Recurve Bow because you got killed or got connection problems etc. , buy one or two Dagger and head back as fast as you can. Anyway you need them for Malady.

Now head for Madred's Razor to keep farming easy. Normally there’s no problem to get this item fast.

Buy Sorcerer's Shoes to get enough Magic penetration for each of you enemies. In combination with Magic penetrations Runes and you Masteries it will be a deadly combination.

After 15-20 minutes you should get Madred's Bloodrazor. It's your most important item. Its passive works such fine with you Bio-Arcane Barrage. Your attacks with Bio-Arcane Barrage will now deal between 11% and 12% damage of the targets maximum health. In combination with Void Ooze and the increased range of Bio-Arcane Barrage it will be easy to gank and track down even tanks.

Now buy Malady. It is a real cheap item and increase you damage so excellent. Its passive helps you to get Magic resistant targets down in a short time.

I solved the problem of Kog'Maw, being very slow for haunting enemies which rush for Zeal and Phantom Dancer. Buy Rylai's Crystal Scepter. You now got the option to slow running away enemies with your ultimate. It also increase the damage of all of you abilities and give you important life points. It’s really good working. Slow with Living Artillerie to attack with Bio-Arcane Barrage and if the slow disappears him again with your Living Artillerie. I first thought of buying Frozen Mallet instead of Rylais so the Bio-Arcane Barrage would slow your target. But dealing more damage with all of you abilities and help teammates finishing off a fleeing target is the better choice.

Nashor's Tooth gives you a increased attack rate and a nice cooldownreduction. The ability power you gain from Nashor's will raise your bonus damage of Bio-Arcane Barrage to 1.8%.

Finally you need attack speed to deal much damage. Wit's End increases your attack speed, gives you some Magic resist and deals 42 bonus magic damage with each attack. Each attack stacks 5 Magic resist up to 5 times, so you gain 25 Magic resist while attacking.

Caustic Spittle: You gain passive attack speed when leveling Caustic Spittle. The active is able to reduce the targets magicresistance. Caustic Spittle got a real close range and don't fit in Kog'Maw's long range concept.

Bio-Arcane Barrage: Your main skill. When active dealing 6% damage of the targets maximum health + (0.01 x Ability power). Your attack range gets increased by 130/160/190/220/250. With this skill Kog'Maw is allowed to deal damage on high range and stay at a safe distance. With Madred's Bloodrazor you deal additional 4% magic damage.

Void Ooze: Great to assist Teammates in fleeing or attacking Opponents. Good combination with Living Artillery.

Living Artillery: Perfect to scout for opponents in brush. Living Artillery is great to finalize enemy Champions, because of its long range.

: Useless for Kog'Maw. Kog'Maw attacks from a large distance and don’t get in close combat to ignite a Champion.

: Great to use while attacking with Bio-Arcane Barrage.

: So many abilities to use it.

: Great for a high AD-Team.

Pros

• High damage output.
• Even tanks are easy targets.
• Skillshots deals good damage.

Cons

• Slow early game.
• Difficult Last hitting.
• Can't one vs. one against an AD Carry like Tryndamere, Caitlyn, Miss Fortune and Ashe etc.
• Focused in Team fights.

Kog'Maw got a slow early game until Level 9. If you get killed often at early game it will be really hard to get a kill in mid or late game.

It's really funny to see enemies running away from you, but you always get them with Living Artillery.

This is a guide for team player which prefers ranked games.
The best result you gain with Supporter and real tanks in your team.
Always remember you’re a hybrid carry and won't burst damage or crit like hell. So keep your brain on while playing to avoid unnecessary deaths.

Kog'Maw's combinations of his skills are the key to victory.

I hope you enjoyed my first Guide and will give it a try.