You're Marga-something.
More importantly, you're a witch. Mermaid is pronounced "ma-meido" in Japanese (though shortened to "ma-mei" on Alice's sign to set up the pun in the next panel). Margatroid is pronounced "ma-gatoroido".
So Reimu is saying, "You're Ma-ga_blah, not Ma-mei_blah."Your eyes are
John TraVOLTS.
Pun on the song 君のひとみは10000ボルト "Your eyes are 10000 volts" and, of course, John Travolta.In a flash,
A Tokyo Metro Fukutoshin Line named Despair!Pun on the song 絶望という名の地下鉄 "A Subway named Despair".
Also a reference to the train delays that occurred in mid June 2008, when the line first became operational. This comic was published in August of the same year.Ah, that thoughtless celestial, huh?
Well, since you're here, might as well let you summon her.Well then, I shall do it at once.So does that make me the mermaid?I can summon her right now.The final Tenshi to fall upon the land. Pun on the following line from "Your Eyes Are 10000 Volts":
地上に降りた 最後の天使
The final angel to descend upon the land.
Angel is pronounced "tenshi".I'm Hong Mei...
Pun between merMAId and MEIling.When did you come in,
China?Kanji of different types of fish....How the mighty have fallen...Um...
It seems that you are not making any progress.
I don't think eldest daughter knows anything about this, but if it suits you, should I call for her?Sorry to say, but I have no clue...
By the way, "The Little Mermaid" is the one whose voice is taken; the witch is the one who takes it.