Hello everyone, this is my first build so please don't be too harsh with constructive criticism! I have been playing pantheon alot recently and I haven't had much success following an item build from the other guides on mobafire here, please note that I'm by no means a "pro" so there are probably ways I could improve to make them more viable.

I follow a standard rune set for pantheon, ArP marks and quints, dodge seals, and CdR glyphs. In my experience the giant leap of ArP in early laning phases really lets you take advantage of Heartseeker strike's full damage, the dodge helps for situations where you need to run and cant pause to use Aegis of Zeonia for a block charge, and the flat CdR is just a little push for all of your abilities, excluding spear toss of course.

I have had my best success with 21/9/0, The points in the defensive tree help make all fights easier, the armor/magic resist/dodge points really do shine in fights where you're being focused or when you need to get out of a fight (If I had a nickel for everytime I got out of a fight with a sliver a health with these masteries...) The points in offense are also very standard, making further use of your ArP and critical damage.

I like to take exhaust and teleport for my spells, although it really is just a matter of preference, exhaust is an excellent tool for keeping someone in your HSS and preventing runners from getting away, and makes ganks a breeze resulting in a nicely fed game. Teleport isn't necessary in most people's eyes while playing as Pantheon due to his ultimate having a global range, but I find it helpful and use it 10+ times a game, when Grand Skyfall is on cooldown and someone is backooring or minions are built up at a turret, just teleport over and fix the problem, this spell is essential for strong map control.

This build pulls pantheon away from the squishy zone while still offering him a TREMENDOUS amount of damage and ArP. Frozen mallet gives a respectful amount of hp along with offering a powerful slow component, Hexdrinker offers a bit of damage, magic resistance, and a bubble which can be the difference between life and death, ghostblade offers decent ArP and damage with a nice active, Tiamat gives some damage, but it's passive is it's real scary part, farming efficiency is increased along with extra burst in team fights, black cleaver is horrifying in damage and ArP (tanks be warned).

Remember this is just a cookie cutter build, improvise and have fun!

Since HSS is your bread and butter nuke, you'll want to max it as soon as possible, however grabbing spear toss and aegis of zeonia at levels 1 and 2 will greatly improve your laning phase, making last hits and finishing blows very smooth.

Pros:

Great farmer
Exceptional ganker
Map control
Stun
Block turret shots

Cons:

Tends to be squishy
If HSS misses you will have a hard time winning any fight
Mana starved early game