A girl transferred from Switzerland (not time-travel)
Wigen Wagen is a usage in Old German. It is speculated that it means a cradle. It is also translated as the incarnation of a mermaid, a succubus siren, etc. It changes according to the translation of the lyrics (囧). I just think the song is good, but it actually has nothing to do with the story.
Luca de Laharpe is the girl's Swiss name (mother's surname). Midori Somezaki is her Japanese name (father's surname).
What it means to be a pseudo-comic is that there will be many cutscenes of things from other worlds in the plot, but the main thing is not just about them. The main thing is still the world of Net Kings and SD.