Rengar Full Clear Guide – 2:47 Blue Start
Blue Buff
Gromp
Wolves
Raptors
Red Buff
Krugs
Can Rengar full clear before Scuttle Crab spawn?
Rengar has a very slow first clear, but the good news is that after getting your first back and some items the clear gets faster, so as long as you learn the first one you will have no problems. Clear itself is a bit tricky, but with this guide and practice it can be learned quite fast.
How does Rengars passive work?
Rengar uses 
Ferocity as his resource, unlike other champions that use mana or energy. He generates a point of Ferocity every time he uses an ability or once every 10 seconds when he damages an enemy from a bush. On 4 stacks of Ferocity, he can cast a stronger version of his basic spells, without having to worry about their original cooldown. Once you lock down this mechanic, and learn when and how to use your stacks, the clear is very simple. Additional tips and tricks are listed down below.
Which runes are best for Rengar?
After some testing, 
Attack Speed shard turned out to be 1-2s faster then 
Adaptive Force in the first row. For the second row, there is really only one choice and that is Adaptive Force. In this guide for the third row I've used 
Health Scaling, but I do see an argument that 
Health Flat could be better, since a lot of Rengar mains opt to do 3 camps into invade, or like to fight early - but even then I'm not so sure its better because if you use your 
Battle Roar correctly during the fight, you shouldn't have the need for extra 50 health from Health Flat.
What spell is best to start?
Savagery is Rengars main damaging ability and of course we will be taking it level 1, then taking Battle Roar level 2 is optimal, because it makes the clear healthier and also gives us bonus AoE for 
Wolves. Taking 
Bola Strike level 3 is by far the best as it gives us vision on targets, so we can use our passive to jump to them and save precious time.
Should I use my second smite during this clear?
I think in most situations, yes. Rengar has a very strong 1v1 as long as he is in a bush already and has 4 stacks, which is much easier to do if you 
Smite the 
Red Buff and have additional time to walk into river. And as long as you have those conditions met and you win the 1v1, you don't need Smite to secure the 
Scuttle Crab as the opponent will either be dead or running away.
Important mechanics & Tips:
- Clear starts between
0:45 and 0:49 as you want to Savagery the blast one and get one extra stack of your passive, earliest you can do it is 0:45 because the stacks last for 10 seconds and latest is 0:49 becuase you want to get your Savagery back up for when 
Blue Buff spawns. - Rengars Savagery is an auto attack reset, so make sure you use it in that way - also on every camp where we plan on using
Empowered Savagery, the sequence will be Q-AA-Q-AA because it maximizes our DPS (the only exception is raptors where because of red buff running to us we have to do a fast AA-Q-Q combo) - Don't forget to walk into the Blue Buff bush before using your second Savagery cooldown, as this extra stack of Ferocity will come in handy on
Gromp. - You will use Empowered Savagery on every camp with the exception of
Raptors when you jump on them, where you use double W-W for AoE damage. - On
Krugs in case you want to recall and just finish the clear as soon as possible, using 
Empowered Battle Roar is fine, otherwise keep the 4 stacks and be ready to gank or fight in river with them. - Double Smite on Red Buff if you want a faster clear!