If you put a banner down only the champs from the same faction as the banner get that bonus. I.E. you're KF/SL split, you put down KF banner, all your KF guys get banner effect, none of your SL guys do.
Understood. Thank you very much! However, it seems the banners have been nerfed? +5 HP, +1 damage. Didn't it used to be twice that? Are they worth it anymore?