NPC: Firewing Warlock
ID: 16769

Should have a pool with couple of aggro text.

"You know too much!"
"You won't escape alive!"
"Kill them before they get away!"
"I will have your energy and then your life!"
"They mustn't escape!"
"For Kael'thas!"

http://wowwiki.wikia.com/wiki/Firewing_Warlock
http://www.wowhead.com/npc=16769/firewing-warlock
https://youtu.be/ol1X4AWCHfM?t=133