SL Bloodlines Wiki

In Bloodlines, Angels are primarily distinguished by their stunning wings, their ability to consume Ether, and by the fact that they suffer the Angelic Curse.

Each night 2.5 Auraus of Ether are stolen away from them by the Curse, and if they ever are reduced to zero, they are destroyed. As a result, they are doomed to forever hunt humans and consuming Ether to survive.