
Vanguard · physical (AD) damage
Ornn is a Vanguard that deals physical (AD) damage and brings airborne, root, slow. Some of their lockdown (airborne) ignores tenacity, so you dodge it; you can't cleanse or Merc' through it. Below is Ornn's highest-win-rate build from high-elo games; open the counter-build tool to tune it against your specific enemy team.

Ornn gains an additional bonus Armor and Magic Resist from all sources. Ornn can spend gold to forge non-consumable items anywhere. Additionally, he can create masterwork items for himself and for his allies.

Ornn slams the ground, sending out a fissure dealing damage and slowing enemies hit. After a small delay, a magma pillar forms at the end location.

Ornn advances, breathing fire. Enemies hit by the final gout of flame become Brittle.

Ornn charges, dealing damage to enemies he passes through. If Ornn collides with terrain while charging, the impact creates a shockwave around him which deals damage and knocks up enemies.

Ornn summons a massive elemental at a location which travels toward him with increasing speed. Enemies run over by the elemental take damage, are slowed and are made Brittle. Ornn can recast the ability to charge into the elemental, redirecting it in the direction he hits it, causing the elemental to affect any enemies it runs over to be knocked up, dealing the same damage and re-applying Brittle.
E Searing Charge
R Call of the Forge GodRoottenacity helpsFROM
W Bellows BreathSlowignores tenacityFROM
Q Volcanic Rupture
R Call of the Forge GodHover a crowd-control type to see which ability it comes from.
Resolve
Grasp of the Undying
Aftershock
Guardian
Demolish
Font of Life
Shield Bash
Conditioning
Second Wind
Bone Plating
Overgrowth
Revitalize
Unflinching
Inspiration
Glacial Augment
Unsealed Spellbook
First Strike
Hextech Flashtraption
Magical Footwear
Cash Back
Triple Tonic
Time Warp Tonic
Biscuit Delivery
Cosmic Insight
Approach Velocity
Jack Of All Trades

Based on 7685 games · 50.7% win rate · challenger+grandmaster+master+emerald-diamond+platinum-emerald · patch 16.18.1.
Resolve
Grasp of the Undying
Aftershock
Guardian
Demolish
Font of Life
Shield Bash
Conditioning
Second Wind
Bone Plating
Overgrowth
Revitalize
Unflinching
Inspiration
Glacial Augment
Unsealed Spellbook
First Strike
Hextech Flashtraption
Magical Footwear
Cash Back
Triple Tonic
Time Warp Tonic
Biscuit Delivery
Cosmic Insight
Approach Velocity
Jack Of All Trades

Based on 158 games · 43.7% win rate · challenger+grandmaster+master+emerald-diamond+platinum-emerald · patch 16.18.1.
Inspiration
Glacial Augment
Unsealed Spellbook
First Strike
Hextech Flashtraption
Magical Footwear
Cash Back
Triple Tonic
Time Warp Tonic
Biscuit Delivery
Cosmic Insight
Approach Velocity
Jack Of All Trades
Resolve
Grasp of the Undying
Aftershock
Guardian
Demolish
Font of Life
Shield Bash
Conditioning
Second Wind
Bone Plating
Overgrowth
Revitalize
Unflinching

Based on 62 games · 53.2% win rate · challenger+grandmaster+master+emerald-diamond+platinum-emerald · patch 16.18.1.