In the Greek pantheon, Iris is a messenger of the gods and the personification of the rainbow as well as a goddess of sea and sky. Iris’ name has a double meaning that encompasses both of her duties. In Greek, “iris” is rainbow and “eiris” is messenger–these two words would have been pronounced as English “iris”.
Iris was often shown as a young woman carrying a caduceus and/or ewer, and had wings on her shoulders. As the personification of rainbows, she could also be shown simply as a rainbow.
The parents of Iris were the Titan Thaumas and an air nymph Elektra. Iris as the Harpies for her sisters, according to Hesiod. Her husband is Zephyrus, the west wind. They have a son, Pothos, who is one of Aphrodite’s retinue. [His parentage is questionable, different authors have him with different family groups. It actually is more likely that Pothos is not Iris’ son since she was often considered to be something of a virgin/virginal goddess.]
Iris is frequently mentioned in myths but does not seem to have any of her own. She is often portrayed as the messenger of the gods as a whole and as Hera’s personal messenger as well as her handmaiden. She reaches the earth by running/flying down the rainbow to deliver her messages. The clouds are replenished with water by Iris’ doing.
She also fulfills a very important function: by order of Zeus, Iris is to always carry with her an ewer filled with the water of the River Styx. The Styx was the river the gods swore by and oaths sworn on the Styx were unbreakable. Iris uses this water to put to sleep any who are guilty of perjury.
In one myth she saves her sisters the Harpies by turning back the Argonauts Zetes and Calais, who had been pursuing the Harpies.
Light and Dark Sides
Iris doesn’t have much of a personality, so her Light and Dark sides take some guessing. As a messenger, she is responsible for communication, whether good or bad. She’s not associated with bringing either good news or bad news, which works in her favor in terms of the Light/Dark scale. She simply facilitates communication by the passing of messages.
She is also responsible for punishing perjurers, which is a heavy responsibility. Iris brings what seems to be a rather light punishment to those who perjure themselves, but since this punishment was commanded by Zeus, Iris can’t really be judged by it. She simply does her duty and in the process punishes those who lie. It is somewhat fitting that she have this duty, since as a goddess of communication she is punishing those who communicate falsely.
In addition, she saves her sisters the Harpies from being caught and probably tortured or killed, and all she does in doing this is convincing the men to turn back. She doesn’t harm them or seek revenge, as other gods would have. Iris just sends them away and goes on about her business, as if they were annoying flies who buzzed away.
While Iris seems to be very passive, she really isn’t. She’s doing all of these things and accomplishing things, so she is hardly inactive. And doing nothing is still doing something. Overall, I’d say Iris is a Light goddess–she does her duty to Zeus with the Styx water, does her duty to the gods by running their messages, replenishes the clouds with water, and is the rainbow. Nowhere in any of that does she do something that is negative.