dragon whose horns have not grown, cruel
螭 centers on a specific kind of dragon in mythology: one whose horns have not yet grown, often associated with cruelty or ferocity. The cruelty sense is a natural extension of a fierce, untamed dragon.
螭 combines 虫 (insect/reptile) with 离, which likely contributes the sound. The character refers to a hornless dragon in Chinese mythology, but the exact historical development of the components is uncertain.
The left side 虫 suggests a reptile or dragon-like creature, and the right side 离 looks like a fierce, hornless head. Picture a young dragon with no horns yet, but already cruel and wild.
For チ, imagine a tiny hornless dragon that makes a high-pitched 'chee' sound when it tries to roar: chee -> チ, and the little dragon is still cruel despite its size.