At level 60, the Nephalem Valor buff kicks in. Killing champion packs increase the effect, which gives a boost to gold and magic find, and increases the number of drops from bosses.
How many stacks can you get? What causes you to lose stacks? How much gold find and magic find does each stack give? How many extra drops from bosses does it give? Is it any boss, or only Inferno bosses?
The entire Nephalem Valor concept has been removed since Patch 2.0.1 (live on Feb. 25, 2014). Along with this change, two new concepts have been added to the game (Official Patch Notes):
Pools of Reflection have been added to the game
- Pools of Reflection provide a 25% bonus to experience
- This bonus persists until you reach a set amount of bonus experience (equal to approximately 10% of the current amount of Paragon experience needed to reach the next Paragon level) or your character dies
- Gathering additional Pools of Reflection bonuses increases the amount of total experience bonus a character can receive until character death, stacking up to 10 times
- This experience bonus persists on logout
Nephalem Glory has been added to the game
- Occasionally during battle, monsters will drop Power Globes when damaged or killed
- Power Globes grant the Nephalem Glory buff, which causes players to deal additional damage in the form of golden lightning bolts and increases their movement speed for a short time
- This buff can stack up to three times