The Rainbow Dragon was named the Crystal Dragon. It's a bit strange how they translated it; it seems like it was originally written as Rainbow Dragon, which means Rainbow. But the translators translated many things strangely in the game.
What do you all think about the Red and Magmatic Dragons?
Асха - Порядок! Ургаш - Хаос! Силат - Воздух!
Шаласса - Вода! Аркат - Пламя! Силанна - Земля!
Сар-Илам - Дракон-Маг! Эльрат - Свет! Маласса - Тьма!