I thought it was not necessary, but it seems that I should clarify it to avoid further confusions.
the blonde character is NOT Kurumi NOR Mugetsu, she is a nameless resident of the makai of touhou 5 which only appears in the ending of Reimu.
I think the best thing to do is to create tags about these characters, there are a handful of images where they appear.

More info here
https://en.touhouwiki.net/wiki/Minor_Characters#Unnamed_Makai_residents_in_Reimu.27s_Ending_of_MS

tremolo_measure said:

I thought it was not necessary, but it seems that I should clarify it to avoid further confusions.
the blonde character is NOT Kurumi NOR Mugetsu, she is a nameless resident of the makai of touhou 5 which only appears in the ending of Reimu.
I think the best thing to do is to create tags about these characters, there are a handful of images where they appear.

More info here
https://en.touhouwiki.net/wiki/Minor_Characters#Unnamed_Makai_residents_in_Reimu.27s_Ending_of_MS

She’s typically known as Mika, the other one is known as Senkou