Hi guys. This is my first build. I have just 300 wins, and my english is terrible. But I will give my best.
The name is because in my last game, after a killing spree on early, my lane partner said: "This is Sparta!" and I found it funny.
I have tried this build and been great.
It may look a bit crazy so much doran´s blads.. but trust me and try it.. works.
I have tried jungling with panth.. but I like it more in the lane.

I think masteries are on your own... this are what I personaly like with panth.

Same whith masteries.

Why so much Doran´s Blade? The problem with pantheon is that mana runs out very quick. So, when there´s nothing to do in lane, and you are far away from blue, you go back and return with more health, more ad, and more lifesteal. If you had made a good lane and saved some gold, feel free to buy 2, or 3 doran´s blades on a time. It worth it.
Then, the giant´s belt . Once you get it you don´t need to go back exept for buying. Remember that when you have it, you allready have 4 doran´s blade .. so you have lifesteal enought to stay in lane or geting the jungle as much as u want.
About the last 3 items: Warmog´s armor , Sunfire cape, and Force of Nature, are sitacional items. I use to get them because for this moment of the game you make enouth damage, but you may get a Infinity edge, a Phantom dancer.

you can also use teleport. I personaly don´t like to.