Pantheon is a melee champion that does not need DPS. Instead, you can kneel down your enemies with AD builds. TIP: this build will take a few games to get used to but when you do, Pantheon can be very lethal.

This item build is made to help get away quickly with little hp and then gain it all back with life steal. Dorans blade gives you a lot of hp and some AD to be able to harass with spear shot. Then when you recall or eventually die, you need to rush boots of speed and Zerk greaves for that extra DPS and speed that should help you catch up to your enemies with your AD. Then you get the brutalizer. This item alows for you to have that AD at the beginning of the game. By now, you have decent damage output and easy creep farming. But you need more. The 2 Bloodthirsters will put up your life steal. By now, you should be pretty fed. If you have some more money, buy the infinty edge.

Pros:
-Can deal heavy damage
-Easily kills squishy champs
-Grand Skyfall allows you to come into slowed champions and go for the kill
Cons:
-With this build can be very squishy
-Low mana causes a lot of recalling
-Bad escaping

Ghost allows you go get away and into ganks quickly and ignite allow you to seal the kills. Nuff said. Stay away from heal bacause of the lifesteal. Exhaust is also a good choice for those who have problems with chasing.