This is an expansion and requires the base game to play: yes

Choose your character, team up with your friends, and start your adventure! Gain experience points on each mission. Spend your experience points between missions to improve your character with awesome new skill and gear cards.

The 150-card The Ruin of Thandar Campaign Deck contains:

• Rules for solo and cooperative Campaign play
• Three different missions, each designed to be more challenging than the last!
• Skill and gear cards to improve and customize your character