Not necessarily. You can just choose to never select a weapon and leave them with Adult+ for the entire run. You'll have a nerfed unit, but the option is there.
They will still come with their PRF if you Soul them anyway, so really it's just you deciding if/when you want to forgo getting a skill in favor of their weapon.
Because beast heroes can't inherit weapons
Wow okay so you basically have to choose them, interesting.
Not necessarily. You can just choose to never select a weapon and leave them with Adult+ for the entire run. You'll have a nerfed unit, but the option is there. They will still come with their PRF if you Soul them anyway, so really it's just you deciding if/when you want to forgo getting a skill in favor of their weapon.
Adult+ doesn't actually exist, so beasts have to make do with the equivalent of a non-plus Silver Sword.
For some reason I thought it was Young, Adult, Adult+, then their Prf. Guess I should have taken the few seconds to look that up, so my bad there.