From The TimeSplitters Wiki

Jinki
Unlocked by	Elite League > One Shot Thrills > Nikki Jinki Bricky with Gold or Better
Species	Human?
Size	Normal
Accuracy	7
Agility	6
Stamina	4
Fire Proof	N/A
Shock Proof	N/A
Default AI	4
Native TimeZone	Unknown
First Appearance	TS2
Relations	Nikki (Sister)
Games	TS2

TS1 Gesture	N/A	TSFP Gesture	N/A
TS2 Gallery	Twins from a tiny Oriental village, Nikki and Jinki were sold to the Ringmistress when they were both babes in arms. Strangely, each claims to be the elder sister.	TSFP Gallery	N/A

Jinki is a character in TimeSplitters 2 that can be unlocked for arcade. She has a monster like face on the front of her head, and a human like one on the back, same as the one found on the front face of her sister, Nikki. Also, she is a freak in the Circus. To unlock her, you need a gold medal on Nikki Jinki Bricky challenge in Arcade mode.