The boss piñata (High Priestess of Avalon)

Certainly the easiest boss in the Avalon raid, the Avalon High Priestess, nicknamed the Pinata, is a boss that still requires some knowledge, which is as follows..

Explanations

Since the boss fight is relatively simple, the correct walkthrough can be found in this video :

Error: Failed silence on the shadows

Silence on shadows prevents them from regenerating.
If you miss the silence just before they appear or if your DPS is too low, you must start over.