Vikings Heroes

Hi! I read the guides and tips to keep your strongest heroes at base during Vikings. But I have some questions:

1. Between Petra and Jabel, is it really better to use Petra if she’s my stronger hero? Petra is strong but Jabel has more stable and better defense skills, right?

2. Rosa is my strongest archer, do I send her to HQ even tho I will only send infantry and cav?

Thank you.