Hello my name is Trinity Inc and i am lvl 30 summoner lvl player on the EUW server who likes Solotop/Mid/Jungle/AD Carry and Depends on the AD Carry even support is fine. I've seen some horrible misunderstood builds on Kog'Maws the times i've taken a look at them, neither they are on my team or enemy team. This champions has huge pontential in Mid/Late game wich he lacks in Early game. In this guide i will get more in-depth about this champions abilities and how you should play him, Enjoy! :)

In this section i will go bit more In-Depth on the rune section of my guide.

Marks

Greater Mark of Desolation
Purchase Cost: 410
+1.66 armor penetration

These Marks are definetly the way you should go on any AD Carry as every champion you are against will have Armor and why wouldn't you want to penetrate it, Has some synergy with your "Q" Skill wich reduces the Armor and Magic Resist Reduction of enemy by: 5 / 10 / 15 / 20 / 25.

Total ARP with Q Active on rank 5: ~40 Armor Penetration, and you also should have the Mastery armor penetration wich is +10% Armor Penetration.

Seals

Greater Seal of Alacrity
Purchase Cost: 410
+0.76% attack speed

These seals also have synergy with your "Q" Skill it has really valuable passive for Kog'Maw wich provides Attack Speed Bonus: 10 / 15 / 20 / 25 / 30%. When you Press your "W" skill and you hit your "Q" on your enemy you will wreck them apart pretty fast (combine this with Nunu's Blood Boil ability for even more wrecking) especially in endgame, This is just my personal preference. If you are against harass heavy lane or a Kill Lane you could go Armor Seals over this for the extra survivability. Kog'Maw should be the harasser, not the Harassed.

Total AS from runes: ~7% Attack Speed
Total AS from runes "Q" passive: ~37% Attack Speed

Glyphs

Greater Glyph of Strength
Purchase Cost: 205
+0.28 attack damage

These Glyphs purely focus on last hitting and harass section, These help you last hitting under the tower and hitting for a bit more on enemy while you are poking. The AD you get from the glyphs is not much, but if you combine it with the Quintessence AD Bonus it really helps you more than you would think.

Total AD From Glyphs: ~2,50 AD
Total AD From Glyphs & Quintessence: ~9,25 AD

Quintessences

Greater Quintessence of Strength
Purchase Cost: 1025
+2.25 attack damage

For poking and Lasthitting under the tower, I explained most of that stuff on the Glyph-section, Go read it if you didn't already.

Total AD From Glyphs: ~2,50 AD
Total AD From Glyphs & Quintessence: ~9,25 AD

In this section i will go through the most important parts of the mastery build in using.

Offense

Weapon Expertise
+10% Armor Penetration

AD Carry? Armor Penetration is the way that increases your damage most in late game as the Bruisers have built tons of armor, It also synergies with the other mastery "Sunder +6 Armor Penetration" Early game your "W" combined with these masteries will deal tons of dmg, Dont pass it.


Lethality
+10% Critical Strike Damage

This increases your damage greatly for late game, With your Phantom dancer+Infinity edge you should have 55% Critical Strike chance and Infinity edge already increases your Critical Strike dmg up to 250%, This increases it even more. Too good to pass also.


Defense

By going Defense you will achieve:

Heal: Increases health restored by 10%
Hardiness: 6 Armor.
Durability: 108 Health @18.
Veteran's Scars: 30 Health.

Combined into 138 Health, wich ain't much but if you take a look at the build you won't see much health items on Kog'Maw, as you should be able to stay way back from the fights (You'r "W"'s Range should be enough to keep you safe.

These Defensive Masteries mostly focus on the laning phase where kogmaw may get harassed by enemy ad carry/support.