Reckless Attack will work with quarterstaff enchanted with Shillelagh. After some testing, Rage bonus damage didn't seem to be applying, but I also noticed the same lack of damage applied to my Rapier +1 and dagger. They did appear to work with my handaxes. I'm left with a conundrum: I don't know why I was able to get the Rage damage in my last post. Are the rules for "Rage: Wolf's Heart" different to the rules for "Rage", was there some error on my part, or is there something I'm overlooking?
So, little development on this! Cardshark on Discord did some testing and it seems I moreorless had the right of it. They got bonus damage on Dexterity-based attacks for the initial Rage, for a Bear Barbarian's rage, and for a Berserker's rage.
The other Wildheart Hearts, though, did
not give them bonus Rage damage. This inconsistency is probably an error: I imagine either the Barbarian Rage is meant to be limited to Strength attacks, or it's been simplified to any attack with a melee weapon but the other Rages were coded as if the Strength restriction were still in place.
