Ornn is a great tank whit a lot of CC, resistence, and damage(in most of my games whit ornn i deal more damage then the bruiser). While playing ornn you don't have to recall to buy items (but not consumable) thanks to his passive so playing it gives a great advantage. Even if you are losing the lane Ornn will be usefull: the last part of his passive can give your allies an upgraded item for free, that means that your allies gains free stat

Hi i'm andREX512 form the EUW server, i'm just a 16 year old italian guy who likes a lot playing LoL in the top lane whit ornn, i'm a onetrick ornn player but i'm not so strong, i just wanted to share the way i play my main.

P.S. if you find some error please help me and write a comment so i can fix it.
P.P.S. this is my first guide i make so don't expect anything of special in the layout, that require some programming skill that I don't have.

PROS
-a lot of CC
-great tankiness
-shop from anywhere
-upgraded items for his team
CONS
-hard to master
-can easilly get poked down
-early mana issues
-can't 1v9

main runes 1: standard for more damage and pushing
Grasp of the Undying is the keystone you will use the most: it synergizes very well whit the brittle of W and R, healing you for a ton of life and dealing that damage that no one expect.
Demolish help a lot when pushing in all the game: in the early game whit the plate you gain extra gold and in the late you can split push fastly
Bone Plating give more tankiness, very usefull for the early trades
Overgrowth allow you to gain a ton of health and is the only rune you can choose because Revitalize and Unflinching are useless for ornn, very usefull in the endgame when you have stacked it

main runes 2: you take this rune to freeze the lane and cs under tower
Aftershock is the keystone that you will use in matchup where you can't proc the grasp
Font of Life: you won't push but in the teamfight you will be more usefull
Conditioning is useful because you won't trade but you can gain free ar and mr

secondary
Biscuit Delivery very useful in the early game for his free heal
Time Warp Tonic synergiezes well whit the corrupting potion and the biscuit giving more health for the trades

Corrupting Potion is just the best starting item for ornn, synergizes whit Time Warp Tonic and is very usefull for early trades
Sunfire Aegis is the item you will be building the most time as first item: good stat, upgreadable in Forgefire Cape and his passive help whit cs
Abyssal Mask is the standard second item, gives the mana you need in the early game, upgradable in Infernal Mask for more free stat
Iceborn Gauntlet is the first item if against an all ad team, followed by the Sunfire Aegis, his passive work very well whit Grasp of the Undying+brittle and it is upgreadable in Frozen Fist for better stat
Locket of the Iron Solari is the item that you will build the less, is the masterwork( Circlet of the Iron Solari) as a second item if against an all ap team; there is no other reason to build it
Warmog's Armor i just love his passieve, it gives you so much life regen out of combat that you won't have to recall for the rest of the game
Gargoyle Stoneplate his active duble the health during a fight and gives good stat
Thornmail if the enemy carry and is a champ like Ashe you shuold buy this
Randuin's Omen if the enemy carry is crit dependent like Yasuo buy this
Spirit Visage if the enemy carry is an ap like Ahri buy this
Adaptive Helm if the enemy carry is an ap like Vel'Koz buy this

Living Forge is Ornn passive an is what makes ornn ornn. gives 10% of ar/mr from all item, allow him to build masterwork and item from anywhere
Volcanic Rupture is Ornn Q: great to farm, combo whit E and slow the enemy. second to max
Bellows Breath is Ornn W: great to farm and his hits best basic ablity: synergiezes whit grasp and gives CC and damage; a lot of damage for a tank. First to max
Searing Charge is Ornn E: combo whit q for an area of knocking up CC, is also a good way to escape from gank. last to max
Call of the Forge God is ornn R: is the most diffcult ability to master, has two activation: the first gives brittle to the target, the second knock up enemy, best tool in teamfight.

Brittle is an status effect that makes enemy take more damage form ornn AA and stunning them for an very short lenght of time