For anything previous to level 10, I always recommend Moon Druid. Tack on a level of Barbarian if you want.

Druids come packed with decent armor and health, not much worse than any Fighter, and you'll get more temporary HP out of your beast forms than you would with Samurai or anything else.

Best case scenario, you murder everyone as a bear. Twice, since you can use it per Short Rest.

Worst case scenario, they killed two bears and now have to take on a full-caster Druid with full HP and slots.