Kii

Kii is a Dryad who appeared in chapter 20 being rescued from an illegal Monster trafficking operation. When Papi found her, she named her Kii, since Papi stated "she looks like a tree", she made friends with Papi when she rescued her, and planted her in the illegal waste dump.

Appearance
Kii's has the appearance of a young girl, shorter than Papi. Her hair seems to be made of leaves, and her arms and legs are plant like appendages.

However, after absorbing experimental chemicals, she underwent a drastic change. She transformed into a gigantic plant-monster, with her former body located inside the head. Her breasts were also much larger and implied to be filled with the chemicals.

Personality
Like Rachnera Arachnera, Kii has severe misanthropic issues due to her past dealings with humans.

When she was planted by Papi near an illegal dumping ground for a prototype super fertilizer, her hatred and anger towards humanity was also increased along with her size. Upon returning to normal, she realized that not all humans were bad, but was still mistrusting of Kurusu, if only for the actions he took to remove the nutrients out of her body.

Skills and Traits
She can use her vines to grab and wrap up her enemies,

Plot
Sometime before the start of the chapter, or even the series, Kii and two other monster children were kidnapped and being illegally trafficked until they were rescued by both MON and Cultural Exchange Security Squad. However she was accidentally being left behind by Ms. Smith when the traffickers were apprehended.

She was eventualy found and planted in the mountains near an illegal dumping ground by Papi (so soon forgot about her). After absorbing experimental chemicals, she underwent a drastic change, transforming into a gigantic plant-monster as a result and attacked any human's she encountered.

Trivia

 * Like Draco when she began attacking Kurusu, she was suspected of being D but at the end was removed of suspicion due to being unable to write.
 * Her giant form appears to be based on the forest god from Hellboy II: The Golden Army.