Bears are primarily used as tanks with high, single target, damage.
Bears typically use weapons that scale damage with Strength, like the axe, sword and sickle. Bears generally use runes that scale damage with Strength, like Charge for stun and moving close up for melee attacks, Slash for damage and Harvest Life for healing. Bears, however, are not obligated to use these runes, as every rune offers its own functions, pros and cons and opportunities for better builds. You can consult the Advanced Guide to aid you in your rune and stat choice.