Dropping units on mineral lines is an fine art to most Protoss players. Reavers and High Templar both have the ability to kill workers before the other player can even respond, thus quickly shifting the balance and garnering props from most Starcraft players. However in Starcraft II we are missing a few units. The Shuttle and Reaver have been removed and in their place we get the Warp Prism and Colossus.



Aww Reaver Drop you will be missed but not forgotten.



Now many new players may be confused about how the Warp Prism works, I know this was the case for me because I thought that warping was the new drop mechanic for Protoss. However this is far from the case as Warp Prisms can carry units as well as warp them in. However it can only carry a single Colossus, so get used to building them in pairs if your trying to recreate some nostalgia.



Knowing what units to drop and which to warp in, will make your life as a protoss player easy.



The question that you maybe thinking is why would I ever drop when I could warp in? Well keep in mind that only units from a Warp Gate can be warped. Here is a quick list.

Not a bad list to choose from, however you don't get to warp in Immortals or Colossus so its obvious that you should carry these units while warping in Stalkers for anti air support. But I should also add that you should not warp in High Templar but rather you should carry them if your planing on storming a worker line early. The reason for this is that a warped in High Templar is not going to have enough energy for a Psionic Storm right from the start unless you get the Khaydarin Amulet upgrade for 25 more starting energy.
Now I would recommend that you warp in a few Sentry's because they can cast Force Field to trap the mineral line so nothing can get in or out. Or if you expect to get some fire coming your way, you can drop them in so you have Guardian Shield ready for when you arrive.



Force Field makes killing these drones easy as pie.




Keep in mind that this takes some practice getting the timing right, but it is worth it just to make sure you kill as many workers as you can. Also if your going in with a pure warp in drop remember that if things get hot you can always load your selected units back into the Warp Prism for a quick dash.

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Source : Getting the Drop: A Guide To The Warp Prism