A simple weakaura to show text at specific time into the fight. Can be adjusted in the following way:
1. Go to "Custom Options" on top;
2. Under "Display duration (s)" enter how long you want the text to show after it reaches the timer (in seconds);
3. Under "Add reminders", add however many reminders you want for this fight;
4. For each reminder enter the timer in seconds, and the text to show;
5. Go to "Load" on top.
6. Click at the box near "Encounter ID(s)" and type in the boss encounter ID (tooltip lists all encounter IDs for Castle Nathria).
7. (Optional) If you want it for multiple encounters, simply right-click the weakaura, press "Duplicate" and repeat the set-up.