At first, I didn't notice this part because I was too focused on Celty and Shinra's "lovey-dovey upgrade", until my friend told me about this part...
They are making something weird, or should we call it a weapon - right there on the table?
What I want to ask is, are they assassins? Or do they have another identity besides being obsessed with Yuhei-sama ?
They're Orihara Izaya's little sisters, Mairu and Kukuri
They appeared in the special in the first season.
If you're super-observant, you can actually spot Kururi and Mairu as early as episode 8 of the first season. They appear in the background of one shot (at right).
They aren't introduced by name, but an enterprising Japanese-reading person who recognizes Kitamura Eri's voice could take a look at the end credits and spot their names there.
It sounds to me like Mairu is just saying "Yuuhei-san" repeatedly (lol foreshadowing), but I guess Kururi must have a line that I'm not catching, too (Simon is speaking over them), since Kanemoto Hisako is credited as her in this episode.
