Chen is a nekomata from the Touhou Project series, having made her first appearance as the boss of stage 2 in Perfect Cherry Blossom, then going on to make further appearances in the same game as the midboss of the extra stage and as part of Yukari Yakumo's attack patterns in the series' only phantasm stage. Chen is Ran Yakumo's shikigami, so she becomes more powerful as her proximity to Ran increases; however, because Ran too is a shikigami to Yukari Yakumo, Chen's overall level of power is fairly low. Chen is typical of most cats in that she hates water, which is capable of dispelling Ran's shikigami possession of her, and also in the sense that she's highly fond of catnip, which is capable of making her lose the will to fight.
During the events of Perfect Cherry Blossom, Chen was guarding the abandoned village of Mayohiga, though she was unable to put up much of a fight against the protagonists due to being far away from Ran; she later returns during the extra stage in order to prevent the protagonists from meeting her master, where she is once again defeated despite her close proximity to Ran making her more powerful. Chen has attempted to turn Mayohiga into a cat-only village by bringing many cats there and trying to make them her servants, though she has been relatively unsuccessful in regards to the latter.
On the surface, Chen is a typical Touhou character, with heavily projectile-oriented gameplay that occasionally utilizes cats and a spellcard system.
However, Chen has one unique oddity that sets her apart from other characters, and actually makes her a very high level boss character: If controlled by the AI after the first round, they enter a spellcard mode of sorts that is very strong and heavy on projectile spam. A meter labeled "Spell Break" will appear, and Chen will be invincible, attacks instead damaging this meter until it is depleted, which will make Chen vulnerable as it recharges. Because of this, it is recommended you fight her with another Touhou-styled character or even a Cheap Character, otherwise this fight will be more or less impossible to win. Before this, their AI is weak.
Phase 1 will have her create a single ring of projectiles, which will then travel in an angle. After being knocked down, she will start again after the meter regenerates, now creating two or three rings depending on her health.
Phase 2 will begin once the first phase is defeated, and her attack pattern will change. She will burrow into the ground and travel underneath the player before jumping into the air, spraying the red projectiles from before along with white spheres that stick closer to her. Once she gets up, she will begin to go faster and faster depending on how low her health is. Moving around constantly is essential at this point, and if you are cornered, you will more than likely be KO'd, as being cornered will result in her repeatedly hitting the character you chose with both projectiles and her emerging from the ground, making this phase without a doubt the most dangerous.
Phase 3 has her move to the top of the screen, speeding by at extremely fast speeds while shooting yellow projectiles before slamming into the player from above, becoming briefly vulnerable afterwards. The lower her health is in this state, the faster she will pass by, making it harder and harder to hit her. Once her health is depleted during this phase, she is finally defeated.
The once docile bakeneko gets her fighting face on as she shows the opponent her incredible skill at...boxing? One would think that Chen wouldn't be able to put up much of a fight without Ran at her side, but once she steps into the ring, a single chance is all she needs to land the knockout blow and pin the opponent to the ground. Honk it to 'em!