Cold rage is part of the furthering-emotions effort.
The etymology of cold rage is quite obvious and describes the emotion quite well. It is rage, because it burns and empowers us to do things we cannot normally do. It is the feeling of "not doing enough", the feeling of "not being enough" and the desire to make sure this stops. It is cold because, unlike rage itself, it doesn't consume its "fuel" quickly and leads to a very focused mindset. It also have a anesthetic effect on the ability of feeling other emotions, which can lead to the person appearing "cold as ice".
Cold rage builds up instead of vanishing with time and is to be seen as the driving force of Aurora Borealis. It is the willpower hidden in self-progression for self-progression. One could theorize it comes from the constant frustration caused by the limits of oneself and the failures of being more.
Cold rage is what you feel when you consider the possibility that, one day, you may meet the person that you could have become.