Merge is the descendant of a magician and sorceress from the long past. The magician created a virus which would melt puns and the antidote which would cure the virus. He gave the antidote to the sorceress as an engagement gift. The antidote passed down through the family, and Merge was the last to have it.
Merge is the complete form of five sisters: Black, Blue, Brown, Red, and Yellow. Their names match their long hair. When the five are apart, their hair seeks out the hair of the others so they can form Merge.
Merge had the antidote in her hair.