Hello everybody and welcome to my Pantheon build. This build will gonna show you a way to play one of the most evil pyhsical DD in LoL.

The skill sequence above is not correct. I do not remember when Pantheon is able to learn which ability.

So start with your Spear Shot followed by Heartseeker Strike. At level three level up your Heartseeker. Level 4 your stun and level 5 either Spear Shot or Heartseeker.

Max Heartseeker Strike first followed by Spear Shot and Aegis of Zeonia.

My summoner spells are Exhaust and Ignite.
If you enter a battle first stun your enemy and cast Heartseeker Strike. Right after this cast your Ignite. If your opponnent has Flash and flashes away he will get damage over time. Then try to get in range for your stun and Exhaust your enemy before casting Heartseeker and your Spear to finish him off.

Pros:

-Harrasser
-Stunner
-Initiator
-has a high damage output with his "Stun-Heartseeker"-Combo
-aweful Damage Dealer
-can easily win 1v1 if not played recklessly in early game
-has an own teleport (global ultimate)

Cons:

-squishy in early game
-has a low amount of mana
-no good escape possibilities
-has an affinity for CC's
-dies quick in teamfights if focused

The low amount of mana can be handled with Manamune and the Mana regen Quints.
His affinity for CC's can be erased (or weakened) by Mercury's Treads.
His escape possibilities are much better if you just do not run all over the map alone.

If you get attacked by 1 enemy:

Stun/Heart-Seeker-Strike/Spear(/Stun/Spear)

If you fight 2 enemys:

Stun one of them/Heart Seeker Strike/ finish the second one with your Spear off

If you get ganked by 3 or more enemys:

RUN!

I chose Armor Penetration in Marks because the more penetration the more damage deal your skills.

I took Dodge in Seals. Dodge is always good and the best for someone like Pantheon.

My Glyphs are Cooldowns because you really need your abilities to get your triples and quadras.

I took Mana/5 per level Quintessences. Why? You will see if you play Pantheon :D

My masteries are 21/9/0 with your focus on Cooldowns, Penetration, Criticals and Attack Rate in Offenseand Magic Resistance, Armor and Dodge in Defense.

Your items for Pantheon are:

-Manamune
-Mercury's Treads
-The Bloodthirster
-Youmuu's Ghostblade
-Last Whisper
-and either a second Bloodthirster, a Frozen Mallet or Banshee's Veil

The purchase order (simple):

-Manamune
-Mercury's Treads
-The Brutalizer
-The Bloodthirster
-Youmuu's Ghostblade
-Last Whisper
-*your last item depends on your enemys team*

The purchase order (detailed):

-Meki Pendant ---> Tear of the Goddess
-Mercury's Treads
-Long Sword ---> The Brutalizer
-Tear of The Goddess ---> Manamune
-The Bloodthirster
-The Brutalizer ---> Youmuu's Ghostblade
-Last Whisper

Get Tear of the Goddess before The Brutalizer and finish Manamune after your Boots. Youmuu's Ghostblade will be finished after your Bloodthirster. Last Whisper shall be your last item.
If the game is not over yet, pick:

-either a second Bloodthirster to awfully increase your Attack Damage

-or Frozen Mallet if you need some survivability against physical DD

-or Banshee's Veil against enemy mages.

If you have a balanced physical/magical enemy team:

-sell your Youmuu's Ghostblade for a Warmog's Armor and

-get a Frozen Mallet or a Bloodthirster (if your enemys are more tanky get The Bloodthirster)

Mercury Treads

The Bloodthirster

Last Whisper

Manamune

Without Manamune you will not even be able to cast more than 3 abilities right after another.
The Bloodthirster grants you a great Attack Damage and Lifesteal boost.
Last Whisper penetrates your enemys armor like hell.
Mercury's Treads will keep you alive by reducing CC's.