Rift Quest:Friend To Nature  

The target must be at 30% health or lower for the Taming Whistle to work, and it has a 60 second cooldown. Each pet will stay with you for about 5 minutes, and you can have more than one pet. The Whistle remains usable even after you have caught 3 beasts.

You can collect three "friends" immediately, then go hunting Aelfwar. To complete the quest you need to kill 12 Fellpine Aelfwar but the beast's help is not required for quest updates.