Pantheon is one of the best anticary/nuke heroes in league of legends and its fun to play with. I will try show you how i play with him.

Advantages:
1)Strong nuke abilities.
2)Nice finishing moves.
3)Ganging abilities with his ultimate.

Disadvantages:
1)Very fragile ( be defensive at early game to avoid easy deaths ).
2)Can not escape easy
3)Can't take down tanks easy at early game

1st build:
I use 9 Greater Mark of Desolation for armor penetration
9 for mana regeneration because Pantheon have some mana problems at early game
9 to be strong at early game against ability champions
3 Greater Quintessence of Desolation

2nd build:
9 Greater Mark of Desolation
9 to enhance more dodge so can activated easier
9
3 Greater Quintessence of Desolation

3rd build:
9 Greater Mark of Desolation
9
9
3 Greater Quintessence of Desolation

4th build:
9 Greater Mark of Desolation
9
9
3 Greater Quintessence of Desolation

All four builds have 21 points on offense so you can have nice dps, armor penetration and improved exhaust with .

differences between builds:
1st build: gives you more resistances more armor and magic resist
2nd build: gives you more dodge chance and movement speed from defense tree
3rd and 4th builds are the same 21/0/9 the differences are the runes and items.

Movement: Berserker's Boots for more dps or for more armor and dodge. Sometimes you may find more usefull to use for magic resist and tenacity.

Armor Penetration: gives you nice amount of damage and armor penetration for early game so take it as soon as possible.

Attack speed: and

Attack Damage and crit: , , and [icon=Atma's Impaler}

Armor and health regen: Warmorg's Armor and

i use so they can not escape or
to get last hit and low target's heal or
to escape cause pantheon can not escape easy but also to attack you can flash from bushes or through a wall and catch them or
to escape or attack ( personally i prefer flash) :P.

This is the way i play Pantheon as dps and sometimes offtank thank you for reading my guide and i hope you find it usefull. Feel free to comment and be nice its my first guide :P. Have fun mates.