Castle is one of the three winning characters of Pop'n Music 20 fantasia's Minna de Tsukude. The character was created by one of the three winning artists, Cheloniidae.
It has been several months and years since the forgotten kingdom was found. The oasis of the past had no shadow, and grew tired of walking and wandering.
Castle is known as a melancholy-posessed bishop, living in a far away country of sand. They dream of a peaceful environment, and wants to become a messenger of an unknown area. They have a dislike of water, and the crusades.
Castle's appearance is a sand fortress-inspired person with salmon-colored eyes, as the color is identical to their stockings. They have short hair with an odd style as gloppy, and a dark yellow tone. Castle wears a headdress that resembles a small, bandaged fortress. Castle accessorized themself with a maroon cape that has a walnut-colored, square-cut pattern on the bottom and a yellow ring-shaped holder. Underneath their cape is their attire that has the same inspiration as their headdress and their boots. Castle majorly wields a two-forked staff, hanging a magical eye.
In their 2P color palette, Castle receives bright and lousy colors, such as a light magenta color on their cape and window highlights, a cyan color on their headdress and stockings, a yellow color of their hair, back cape, highlight, and boots, and an aquamarine color of their staff.
In their 3P color palette, Castle receives dark and gloomy colors. Castle's skin changes to an extremely pale green color, and their hair color ditches the yellow color into a walnut color. Their cape is forest green, and their headdress retrieves a pale blue color, matching their boots. Their stockings are in a shade of gray, and their castle inspired attire is in a bland color. Their staff is the same color as their headdress.
- Castle's birthdate is identical to Roku's.
- Cheloniidae stated in Castle's character comment that they personally don't have preferred gender for Castle, as it may be because Castle is made of sand.
- Mimi and Nyami make cameos on Castle's LOSE animation.
- Some of the characters, created by the artists who did not win this contest, are shown in Castle's animations:
- Part of AQ's main elements is on Castle's headdress in their GOOD animation.
- Props of Shigu and PARO take place in Castle's FEVER animation. The lute belongs to an unknown character, while an egg-shaped visualizer belongs to Rosey, a character created by PARO.
- Kalon, character of Yamino, makes a cameo on Castle's OJAMA animation.
- A key-inspired lute takes place in a FEVER animation in 2P. The prop belongs to Noah, a character of LOK1.
- A rose bush-themed fairy makes a cameo in a FEVER animation in 3P. The sprite belongs to Ruina, a character of Kicori.
- Jioru, character of Tilly, makes a cameo of an OJAMA animation in 3P.
- Jarawi and Law make cameos on a WIN animation in 3P.
- Renpet, Icnis, and Azari make cameos on a FEVER WIN in 3P.
- Castle is precisely one of the three fantasia characters to receive a profile in the Character Info of the official website.
- Cheloniidae's character comments is one of the few that is written on both Japanese and Korean.