"Starry Knight" (ホーリーナイツ Hōrī Naitsu, lit. "Holy Nights") is an archetype of LIGHT Fairy monsters, released as legacy support for "Seiyaryu" along with its retrain "Starry Night, Starry Dragon" in Selection 10.
The Deck is based on the western Christmas holiday, with the archetype name being a pun on how the Japanese name of "Seiyaryu" translates to "Holy Knight Dragon", acting also as a reference to the song "Silent Night". The archetype seem to be based on angels which are often featured in portrayals of the holiday. This is continued in the S/T support for the deck, which includes more references to the holiday such as Advent period before Christmas and Nativity plays.
The total original ATK and DEF of all the Level 4 monsters equals 2500. This is possibly a reference to the original ATK of "Seiyaryu".
"Starry Knight" are based around summoning Level 7 LIGHT Dragon monsters from the hand and then supporting them. Their main boss monster, "Starry Night, Starry Dragon", destroys a monster every time that he's summoned from the hand, while both "Flamel" and "Arrival" have effects that can return copies to the hand so that you can summon them again.
As "Arkbrave Dragon" is also a Level 7 monster, one possible way to build this Deck would be incorporating parts of the "Felgrand" series into this Deck. Although their Graveyard focused strategy may clash with "Radiant" only destroying when he is Summoned from the hand.