1V1 baron at level 16/17 depending on income of the game have teammates start pushing bottom or mid (bottom preferred) that way the opposing side goes away from you giving you a better chance of not being found as it does take about 30-50 seconds

as of 2/28/2016 I have used this build 33 games, won 27 of them, and only lost 6. as it is a large build I have only been able to 100% complete it 4 times, but guardian angel is not necessary nor is wits end if a high armor character isn't on the enemy team.

your going to want to have mid or top help you get blue buff right away at start, as it helps you complete an entire cycle of jungle without having to return to base to heal, or lane for a minute on minions.

i wanted an op warwick... with this build you do about 500 damage half physical half magical at a 2.0 attack speed + warwicks w that speeds you up even faster.
combined with flash and his ult nobody can run away fast enough when he flanks the lane.
for those of you out there that don't know what the devourer gem does in the jungle blades, after you have 30 charges on it, you do 60 extra magic damage per hit and every other hit is basically a double hit. 1v1 dragon as soon as you get the devourer gem in the stalker's blade, gives you 5 free charges, and if you use your q and w you can 1v1 dragon by the time you have it. guardian angel is so that in the od chance you have to 5v1 you can do it :D. only get it as a last item if the game goes on long enough. It hardly ever gets past 30 minutes if played correctly... with decent teammates.
without guardian angel I believe you have about 2.5k hp, but the damage and lifesteal, you only need enough hp to not die from an op ult, or in a trap against 2-3 enemies.