Paper Mario: The Thousand-Year Door features a variety of characters to encounter, many of which can join your party and aid you on your journey. Each character has their own unique ability and offers something different.

Here are all the partners and their abilities in Paper Mario: The Thousand-Year Door.

Goombella is the first party member Mario meets. Despite her sharp tongue, she has an encyclopedic knowledge of the world and various characters. This knowledge also aids in battle via her Tattle ability, which provides information about an enemy, including their strengths and weaknesses. She also provides offensive moves via her Bonk and Multibonk attacks, which damage one or more enemies. Finally, her Rally Wink helps Mario gain an extra turn in battle, making her an immensely important ally.

Koops joins Mario in Chapter 1 after arriving in Petal Meadows to help defeat Hooktail. Afterward, he sticks around and offers assistance with his many combat moves. These include his Shell Toss ability, which affects enemies with spikes and enemies on fire without taking damage, and Shell Shield, which gives Mario a shield that blocks all attacks (for a limited time). There's also Power Shell, which damages all enemies on the ground, and Shell Slam, a more powerful move that also damages multiple enemies. Koops provides both offense and defense to your party, making him a key factor in victory in battle.