Not Updated For Current Season
I know many people have been saying that Pantheon isn't even viable, but this is the build I suggested to my friend, he is new to the game but is doing very well with this build. The reason I level all of the moves equally is because they are all powerful at higher levels, but if you max one first he lacks in other areas. The reason for getting a Manamune/Tear of the Goddess is so that you can spam your spear shot in a lane to get minions kills. That is also why you get Banshee's Veil, it's to add mana for extra damage, and to give much needed survivability. The MOBAFire stat builder is false, he does not have 4000 mana, it is much closer to 2900.
These runes are to improve his late game a bit, add great Armor Penetration, and add extra damage for Manamune.
Seals of Vigor and Vitality
These are for health in the later game, and good starting health regen.
Glyphs of Knowledge and Replenishment
These are for extra mana to add some extra damage from Manamune, and for mana regen to start off in the lane phase.
The reason you get the tear as early as possible is so that you can stay in your lane for a very long time, and I know that late game , Pantheon needs no mana regen items, it helps early on and Manamune is a great source of attack damage, Manamune is also great paired with some CD which is also why you get Youmuus ghostblade, plus it gives more Armor Pen. Now if you feel that you need some lowered CC duration get Merc treads in place of Bezerker's Greaves, and if you feel that you need some lifesteal a little earlier get a vampiric scepter right after Manamune.
This skill sequence is used because as said previously, all of Pantheons Abilities are best when leveled up, and if one is focused or maxed first then he will lack in other areas.
Pros / Cons
Great Ability Damage
Rarely have to Port back to base for mana
Good CD for stun and spear
Not good tower killer
Not very strong auto-attacking power
Really what makes Pantheon great is his ultimate, it can make for surprise ganks from across the map.
This build will have good end game power, sustainability, and team effect. Pantheon is not the instagibber he used to be, he is balanced now and is great in a team for his clinch stuns and surprise ganks. Remember that the stats given by the builder are false, you will have around 3000 mana and 2600 health when all is said and done.