J4M33

Age: ????
Nickname: J4
Height: 5"0 (Same as Jammy)

J4 is a unknown entity who took on Jammy's appearance upon interaction from a funhouse mirror that J4 resided in. Once Jammy placed her hand on it, the magic between the two individuals set J4 free.

They love stalking Jammy, her prey.

Fun Facts

J4 doesn't blink.
J4 was inspired by Sonic.EXE and other media similar to it.
J4 doesn't have a true name. Instead, she retains Jammy's name with different spelling in leetspeak. Jammy came up with the name as she didn't wanna give J4 her name.
J4 doesn't possess fingers, but has mitten hands.
J4 can teleport and appear in thin air.
Due to J4 not being human, she doesn't understand the concept of being human or human feelings.
J4 has two sets of eyes, the inner black and the orange diamonds. The diamonds can independently move inside the black.
J4's clothes aren't real clothes. They blend in and LOOK like real clothes. However, they are fused into one dress that looks like a tank top and skirt. (Fanart can depict this as separate pieces of clothing!)
J4 has the ability to create black holes in the sky. Nobody knows why or how she can do this. When she does, she knows it attracts Jammy so she can get attention from Jammy very easily.

References

Disguised Form

While disguised, J4 looks eerily similar to Jammy. One continued trait is her large eyes taking up her head. Her ears, horn and ahoge are small but sharp. They lack Jammy's trademark markings on the horn and ears and instead, it's very simplistic. However, she has messier hair and twintails with missing hair bobbles. She doesn't wear any socks and appears barefoot.

Her pupils determine her emotions whether she's neutral, happy, angry or feeling ready to murder someone. When she's in murder mode, her disguise starts to come off as her eyes expose the mask behind the disguise. Her trademark diamond shape appears in her eyes while possessing a large smile and eyebrows. This appears before exposing herself.

J4's twintails will detach from her head revealing bloody strand-like veins which reveals to be attached to a single hair bobble linked to her head. This causes the twintails to float similar to her real form, as she slowly changes her appearance to her real form jumping into action with her trusty scythe in-hand.

From afar, her disguised form can easily fool someone if they don't pay close attention.