Higashi Setsuna

Setsuna is from Labyrinth, growing up serving Moebius. She now lives in Clover Town.

Personality
Setsuna tends to take things very seriously, whether that's about her job while working for Moebius or feeling bad for what she did, even being unable to follow Tarte's manzai script because she took what Miki was saying seriously.

Etymology
Her surname, Higashi (東), is the Japanese word for east.

Her given name, Setsuna (せつな), could perhaps be based on the words 切ない (setsunai), which has a couple meanings along the lines of painful, heartrending, oppressive, and suffocating, and 切なる (setsunaru), meaning eager or earnest.

Her alias, Eas (イース), is based on the English word east, going along with Westar, Soular, and Northa's names.

Cure Passion likely comes from passion fruit, fitting in with the fruit-based names of the other Cures in the series.