Level 60 Executioner, Pain Da, Cyclops, Werewolf, and Angel.
you want to get a druid as fast as possible farming shards so I wouldn't ever take angel up to 80 unless you have HB to spare, same thing goes for werewolf cyclops and painda. Executioner is definitely first. If you don't end up getting legendaries for a while then after executioner I would probably upgrade werewolf since he can be a useful tank in arena. I would maybe do painda next since he has a good talent. I would not put too much effort into the cyclops but he would be next for me. Hopefully you roll an assassin with gems and eventually get some legends. If you get an assassin then upgrade her after executioner. If you get a legendary always upgrade it first.