Rathian is a medium-sized true flying wyvern similar in looks to her male counterpart, Rathalos. Her hide is a dull, muted green in contrast to the Rathalos's deep red, and her lower mandible features a long, protruding chin spike. Her upper back and wingtips are covered in a moss-like fur not seen on the Rathalos, and while her clubbed tail lacks bony spikes, it makes up for this with the presence of sharp and highly poisonous needles, which she can use to poison foes upon contact.