So, I would like to add the newly-made fanmade character Shinki Kak...

Game

Muse Genkaroku

Studio Emiko @emikotenrai

4 years ago

So, I would like to add the newly-made fanmade character Shinki Kakushi as the game's EX boss.

This will be Shinki Jr.'s first appearance before debuting in the spin-offs as the main protagonist.

The reasons why I put Shinki Jr. as the EX boss before debuting as main protagonist of the spin-offs are:

Shinki Jr. has an insanely powerful ability: Creating as well as erasing others' memories, this is what you can expect for a powerful boss character: Just mess with her and poof, your memories are gone, or you will end up being haunted by traumatic memories.
If Shinki Sr. is the final boss of Touhou 5 (Mystic Square), then her "daughter" would have been even stronger than her "mother" (from the Touhou formula of the younger relative being stronger than the older one (good examples: Flandre and Remilia, Koishi and Satori)). And being stronger than her "mother" means that Shinki Jr. should be an EX boss.
Koishi is an EX boss, and Koishi also partially inspires Shinki Jr., as well as both characters having mind-related abilities, so putting Shinki Jr. as an EX boss is reasonable. The best way to pay homage to Koishi is to put Shinki Jr. as the EX boss of a Touhou fangame.