Sea Flash is an old friend of Silver guard Luna and Celestia from when they were kids as well as a teacher to the Luna sisters.
I would say Sea Flash's personality is quite like that of retsu unohana from the anime bleach in the fact that she almost never shows anger or fustration instead keeping her hyperactive students in line with her calming words and demenor.
Thought there is very little that bothers her she can still show a more serious side at times which is normally a sign stay out her way. She loves the sea and visits the sea side in her free time.
Sea Flash has a turquoise coat with a mixed blue mane which she keeps short she is a slender build.
Sea Flash was born a week after Luna to one of the royal libarians she spent much of her early years studying the order of the libary. During the few free spells she had she would play with Sliver guard and the royal siblings but those days ended after Sliver guard left to train and the royal siblings took on ther duties.
She was prensent during night mare moon's sealing away and saw the effect it had on Sliver Guard she saw him off when he left to find away to help Luna and was also present when Twilight took her entrence exam and hatched Spike form his egg.
She currently act as one of the teachers to Luna Drop and Luna Flake
Sea Flash has been good Friends with Silver Guard since childhood she had a small crush on him at one time but it passed after seeing how devoted he was to Luna
Luna and Sea Flash are good friends with Luna and her spending lots of time together
Sea Flash is responsible for keeping the royal libary in order as well as Celestia personal libary the they have a good relationship