This is such a fascinating story, no wonder there are 13 pages of comments after 2 chapters.
So we know now:
1) Kazami "has been watching" the yuriworld's Marika all this time. That's a cliché Japanese euphemism for "has been in love" with her all this time.
2) BUT! This Marika is not that Marika. They just look alike. Kazami, you wouldn't be so shallow as to fall for her just for her looks... right?
3) Marika has someone she's dating in the normal world. She didn't mention gender, but it's safe to assume it's a boyfriend. Big shock!
4) That boy must have a counterpart in yuriworld. A female version of himself. Marika will meet her eventually. What if she likes Marika and wants to date her? What will Marika do?
5) And, if Marika accepts, does that count as two-timing her bf? And what of Kazami? Some complex love polygons here...
6) And what about the yuriworld's Marika, is she in our world now? A girl from an all-female world in a world dominated by males... that's kinda scary.