Rapid

 is a squirrel +Anima and one of Crystala's slaves.

Plot
When Daisy gives Cooro and Nana a tour of the caravan, Rapid and Shera jump down from a tall structure; Daisy introduces them. Rapid notices Cooro's Anima markings, and starts discussing with Shera about how lucky Cooro and Nana are to have their specific Animas. They compliment Nana and inform her she could get a good job, then they head back up the structure.

Shera
Rapid is very close with Shera. They work together as acrobats, and share a similar mindset.

Daisy
Rapid is on very good terms with Daisy, to the point where she sees him like an older brother.