Fusion With Rei: https://www.deviantart.com/aniahmator/art/Rei-And-Cancer-Fusion-734881066

Cancer is one of the spirits that help out Rei as the Zodiac Wielder. He tends to get angry a lot at Rei and often makes sarcastic remarks to him. He does eventually warm up to Rei, and when they fuse, they are a force to be reckoned with. He has a strong bond with Sagittarius, who is technically his adopted brother. Along with the 12 other zodiacs, he aids Rei in fighting the Reverse Zodiac Wielder and the 13 Reverse Zodiacs.