Hey there I really enjoy this build, I like to use Pantheon as an Assassin/Jungler but you can have great staying power with this build. It is very open where after the recommended items are bought you have a lot of freedom to buy what you can I have explained some of the ways I go, but its up to you. I ave gone 17-3 on this build on a good day and usually bring in on average 8 kills a game. good luck

This is a basic layout, I like to branch out from here and try different things. I have gone with HP builds with Warmog's Armor and Atmas Impaler that have worked giving you more staying power. However you could go with Manamune and boost your manna and give some extra boosts to AP. It is very versatile.