Although if you went by when each slayer was born - then it would be the following.

India would be the Dragon, being born in South Carolina - which is in the Eastern United States.

Buffy would be the Tiger, being born in Los Angeles California - Which is on the West coast of the U.S.

Kendra would be the Phoenix, being likely born in the Caribbean - which is South of the U.S.A.

While Faith being born and raised in near Boston, Massachusetts, would be the Serpent.

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But if you go by the Northern Hemisphere seasonal order - which is Spring, Summer, Fall/Autumn, Winter.

Then India (as Spring) would be the Dragon.

Buffy (As Summer) would be the Phoenix.

Kendra (as Fall/Autumn) would be the Tiger.

Faith (as Winter) would be the Serpent.


Note - I don't use the color references of White, Black, Red or Blue - since these have little baring on the actual aspects.

Although - I may use the following elements - Heat, Cold, Wind, & Electricity.