- **Wu So-called**: Monopterus eel transformer has the characteristic of "male and female reversal" in biology. Normally in male form, if the heartbeat exceeds 180 beats/minute, he will temporarily transform into a female, and his force value will decrease; **On his 22nd birthday, his gender will be permanently determined**, becoming the core suspense of the emotion and destiny of the whole drama.
- **Chi Cheng**: Snake converter, stern elite, ace agent of the Animal Control Bureau, son of the family head, burdened with family expectations and emotional trauma.
