Blue caste

The title of this article is a combination of two terms which have not been used together canonically, but is based on their use in the comic. "Let's not mince words: Blue Signs are the ones to watch. Of all the sign classes, they have the potential to do the most good, but also cause the worse harm. They can be incredibly effective, and also incredibly destructive. Tell a Blue Sign this and chances are they would agree with you. They are magnetic and adaptive, able to adjust how they present themselves in any situation. They have a mask for every occasion. They are obsessively dedicated, willing to throw themselves into work, play, and everything in between. Because of this, Blue Signs are highly valuable allies and friends. However, they are very selective when it comes to who they let into their inner circle. You could be best friends with a Blue Sign and still never truly know them. They are powerful and successful, but they also tend toward jealousy. They often resent those they see as more well-positioned than they are. A well-adjusted Blue Sign is fantastically competent and inspiring, but a Blue Sign at their worst is a force for chaos. In love they can find themselves having to choose between their ambitions and their relationships, often with great difficulty."

- The Extended Zodiac

The blue blood caste, also called cobalt, is one of the twelve troll blood castes, higher than teal and succeeded by indigo.

Names
In Homestuck, this color was HS 2276 (generally) HS 3747 (referred) HS 4928 (to) simply as 'blue' alongside teal and indigo; however the term 'HS 2276 (cerulean)' has also been used.

The name 'cobalt' was used on coloUrs and mayhem: Universe A, whereas the Extended Zodiac returned to the general term 'blue'.