Poppy's quote "Fighting is serious business" is a reference to a well-known internet meme, "X is srs bsns (serious business)," meant to troll people that take something seriously with X being the subject at hand (e.g. WoW is serious business, Pokemon is serious business).
Poppy's quote "Let me demonstrate Hammer Diplomacy!" is a possible reference to Nietzsche's book "Twilight of the Gods" or "How to Philosophize with a Hammer", which serves as an introduction to all his other works.
Scarlet Hammer Poppy may be a reference to the game Spiral Knights, as one of the shields in the game is known as the 'Scarlet Shield'. The artwork also bears a striking resemblance to some types of armor worn by the Spiral Knights.
The Chinese version of Poppy's original skin is the background image of the Defense section in the mastery pages.
According to Poppy's lore, her father was given the job to craft a helm glorious beyond all comparison. Poppy was given the honor of helping him craft the helm and was entrusted to set the center jewel, the most important piece.
After her father's death, Poppy unsuspectingly stopped under Galio's shadow while on her way to Demacia. As Galio observed Poppy's continued determination and bravery, he became inspired. Remembering the cause that his master had died defending, Galio arose from his silent purgatory with a new sense of purpose: to join the League of Legends and fight for the will of Demacia.
From the Journal of Justice, pirates from Bilgewater boarded a Bandle City ship headed to Demacia and sacked the vessel of its goods. This particular shipment was on its way to a celebration, a commemoration to Poppy's appointment to service as envoy between Demacia and the yordles. Tristana and Teemo led special forces to apprehend the culprits, though they were unable to salvage the cargo.