Which spirit represents light and order?

Raava is the spirit that represents light and order in The Legend of Korra. She embodies peace, harmony, and balance, while her opposite, Vaatu, represents darkness, chaos, and disorder.

Raava and Vaatu are ancient spirits locked in a recurring struggle. Neither can permanently destroy the other: even if one wins, the remaining trace of the opposite force eventually allows its rival to return. This reflects the series' use of balance rather than absolute good and evil.

During Harmonic Convergence, Raava joined with Wan, the first Avatar. Her essence became part of the Avatar Spirit, passing through successive incarnations and helping the Avatar maintain balance between the human and spirit worlds. Wan's union with Raava is shown in the two-part second-season story “Beginnings.”

Koh and Wan are not alternate answers. Koh is an ancient spirit known for stealing faces, while Wan is the first human Avatar. Vaatu is specifically Raava's counterpart, making him the closest conceptual opposite to the correct answer.