http://www.battlenet.com.cn/wow/zh/f...pic/8329973796

Brief summary: You will get 1/N of the full Vengeance when hit by the mob within 5 seconds who has the Nth highest DPS. This "N" will be recalculated each time you are hit.

For example, you are tanking 3 mobs: one is the Boss and the other two are mobs. The Boss has 1.5 million DPS, one mob has 400K and the other has 300K. The system will now sort these mobs by their DPS:
  • 1. Boss: 1.5 million DPS, so you will get 1/1(100%) of the full Vengeance.
  • 2. The first mob: 400K DPS, so you will get 1/2(50%) of the full Vengeance.
  • 3. The second mob: 300K DPS, so you will get 1/3(33.33%) of the full Vengeance.

This mechanism will be recalculated when you are hit by even more mobs within 5 seconds(1/4, 1/5, 1/6,etc). Additionally, in the example above, if the first mob is not attacking you while the second mob is, you will get 1/2 of the full Vengeance by this attack instead of 1/3.