Enmity Tracking

[Legion88]

That's in-party only. You can be "A" in aggro but still 17th because it only compares you to your party.

"A" is always the target of the enemy.
If you are #1 in your party but not the target of the enemy you will get a "1" and if the target of the enemy is one in the alliance their part in the alliance party window gets a red background.