With a hardness of 2, the lowest of all the gems, Cinnabar has an incredibly delicate body that is easily shattered. Despite this, they are one of the most talented fighters using their unique poison ability, strong acrobatic skills, and tactical understanding to their advantage. Cinnabar is shown to be a force to be reckoned with from the beginning, saving Phos by dispatching entire squads of Lunarians single-handedly in the first episode.

Although they can't completely control it, Cinnabar's poison is a deadly weapon that more than makes up for their inherent delicateness. Moreoever, Cinnabar's isolation, while emotionally damaging, has given them unique insight and understanding of the world. When Phos is working on the encyclopedia, Cinnabar is recommended by the other gems as a source of information. They know about the plants and animals that live around Hollow Cape and also are the first to guess that Phosphophyllite's body is embedded in the shell of the giant snail that swallows Phos. Cinnabar's impressive abilities and knowledge make them a compelling character we can admire.

While Cinnabar's mercurius poison makes them dangerous to those around them, they have little, if any, control over it as it is part of their own physical nature. Despite this, they have been nearly completely excluded from the rest of the gems outside of rare interactions with Dia and Phos. Even in a society that values combat prowess, which Cinnabar possesses, and harmony with each other, they are pushed away making Cinnabar feel worthless to the point of self-segregation.

Throughout the course of the series we see this attitude begin to shift a bit. While they try their best to hide it, Cinnabar has developed hope in Pho's vow to find them a better job, even remembering the promise word for word and repeating it to themselves aloud. This change in Cinnabar's attitude is most clearly seen in the final episode, when Phos finally approaches Cinnabar, opens up to them about their suspicions of Kongou, and asks for their help in finding answers. Cinnabar’s decision to join Phos shows that they are still willing to trust others even after years of mistreatment and reclusivity, able to grow despite adversity.

As a counterbalance to their self-loathing and isolation, Cinnabar is a selfless character that actually goes of out their way to help others despite not caring much about themselves. Cinnabar has especially helped Phosphophyllite, saving them from Lunarians in the first episode and carrying their body to Rutile after she washes up on shore following their betrayal by Ventricosus in the ocean in episode five.

These actions show that Cinnabar is less uncaring than they present themselves. It's also worth noting that Cinnabar doesn't do any of this for recognition or showing off, even going as far as to discreetly move Phos to safety from the shore without telling anyone. While often outwardly apathetic or even rude, Cinnabar's actions show that they do care about others despite their own situation.

Although not as obviously flashy as the likes of the luminously shining Diamond, Cinnabar has an air of beauty all their own. With deep red, medium length hair in an asymmetric style that partially covers their face and the constant presence of slowly swirling blobs of mercury floating around their body, the solitary Cinnabar usually wears a melancholic expression and is one of the more unique looking gems encountered in Land of the Lustrous. Their usual gloomy demeanour also makes the rare moments of hope and cute flustered embarrassment all the sweeter.

Further enhancing their appearance is the way they are presented. We learn from Rutile that unlike other gems, Cinnabar is able to be active without sunlight, using their blobs of poison to reflect enough light to enable them to complete their self-assigned night patrol. This image of the solitary walker in the dark, with faint, silvery lights dancing all around is quite beautiful, as are the other scenes we see Cinnabar in which occur during twilight. This presentation adds a flair of mystery that highlights their unique look that lets them stand out as a character in an already visually interesting anime.

Cinnabar's unfortunate chemistry, while powerful in battle, has been a curse for them their entire life. A life of loneliness, self-hatred, and lack of direction. Cinnabar says themselves in the first episode, “I'm waiting here, for the day they come take me away. At least on the moon they might make use of me.” Cinnabar feels so unwanted and useless that they say they would rather die just to feel useful. Despite that, Cinnabar reluctantly persists and even finds ways to help others in the process.

Cinnabar is is an enjoyable character because they have potential, albeit not fully realized yet. We want to see them succeed, even more so because of their problems and flaws. Like Phos, they are searching for purpose, which for them is not simply having something to do; it's how they hope to find value in themselves. Although Cinnabar hides it, they have hope in Phos' endeavor to discover the proper job for them. This feeling is shared with the viewer and even if things haven't yet been resolved in the story so far, that desire for a better life for both Phos and Cinnabar connects us with the characters in their pursuits. Let's hope for good things come season two!