Final answer:
The provided text excerpts do not contain the description of the character Rain's eyes from the novel Rain Reign, preventing an accurate response regarding the eye color.
Step-by-step explanation:
The question pertains to the description of the character Rain's eyes in the novel Rain Reign by Ann M. Martin. The description of Rain's eye color is not available in the provided text excerpts, therefore an accurate response cannot be given based on the resources provided. Typically, when describing a character's eyes, an author might compare them to elements of nature, use metaphor or simile, or describe the emotion they convey. For more than 100 words, an example could be provided on how authors generally describe eye colors in literature, drawing on the atmosphere or emotions associated with colors, but in this case, without the specific text reference, we can't give an exact answer.