Trex Animal campanion in RotRl

[Atalius]

I'm trying to figure out which feat to give my Trex animal companion in this campaign. I'm trying to choose between Iron Will and Toughness, any suggestions? Are Will Checks common enough to pick it over Toughness? Thank you.

[James Jacobs]

A t-rex with damage is just angry, and it's already kinda made out of hit points. But a t-rex with a failed Will save might just try to eat its friends. I would go with Iron Will every time.