Cause this is by far the best build on this site at the moment:)
hehe now for real this is the build I recommend for Draven:

Because:
Doran's blade = just awesome damage at the beginning, for example for firstblood, or just to kill someone.
Shoes of mobility = to run faster, and to run away, cause Draven is really squichy.
and you'll run faster after opponents (until u attack). (very very uselfull believe me).
Bloodthirster = Cause you wanna drain some hp ofcourse, and for the attack damage ofcourse which isn't bad aswell.
Infinity Edge = For the damage ofcourse, and the critical strike chance what it gives.
Phantom Dancer = For the awesome critical strike chance, runspeed, and attackspeed, which gives you a more easy/fast kil
Trinity force = cause it gives a bit of everything, likely a bit defence and hp too. but best of all the passive what it gives just awesome for draven (after you used an ability your next base attack deals 150%)
Last whisperer = for the armor penentration ofcourse cause they probably have build armor in their builds. (situational item)
or

Frozen Mallot It's slows them, which is very useful for if they run away.(situational item)
But guys ofcourse there are situational items:

A few of these are:

Warmog
Frozen Heart
Maw of malmortius (upgraded version of hexdrinker).

Not to forget The decision to make frozen mallot or last whisperer, they'r really situational items.

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I'll make the guide more detailed later on.