Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This was a build I created after season 1 nerf to pantheon. I was already hard presses to feed myself ealry game to grab the bf sowrds when they mattered and even then pantheons late game was mediocre. I looked for a way to make pantheon good at all stages of the game and strived for items that could be built up constantly maximising your ability at all times rather then in 1 to 2 large boosts.
What makes pantheon shine here is that wriggles lantern and tiamate can work with each other to generate large damage to minion waves very quickly. Pantheons heartseeker passive also works with tiamats making pantheon able to last hit crit creeps hard enough to get another creep to below 15% hp where you can insta crit them again.
With this core build you can easily farm minion waves in a couple of hits while steal dealing good damage against champions.
After you finish the core you have many options and should have tons of gold from creep farming. I recomend maximising your damage or increasing your survivability. You could grab a warmogs or bloodthirster to accomplish this. With your ability to farm and kill champs you should be easily able to max warmogs in the longer games and to quickly farm up bloodthirsters damage.