Wakasagihime, Sekibanki & Kagerou
Yatsuhashi, Benben & Raiko
Seija & Shinmyoumaru
My theory is that the whole reason that impossible spells, being temporarily unbanned when used against Seija, are being used is just to catch her. Her stolen items are incredibly unsafe, so considering that, it could be all out war on Seija because of this.
Either that, or Seija really pissed everyone off.
- Actually, Confirmed.
- Seija turned her inversion power against this itself after Double Dealing Character; thus not only her not being Befriended in the end, but EVERYONE turning against her in Impossible Spell Card and breaking the spell card rules themselves. IE, an inversion of what usually happens.
- Her victory in the end of Impossible Spell Card caused her "rebellion to make the weak rule the strong" short itself out in paradox; and the resulting infinite loop ended the attack against the Spell Card System itself; not to mention the System is strong enough to correct itself eventually. However....everyone remembers breaking the Spell Card System to fight her. And the seeds of that make it Worth It to the Rebel Counterattacking Amanojaku.
- Some of that has also spilled over to Shoot Shoot Nitori. This is Twilight Frontier's first time making a Shoot 'em Up, as well as their first time using a previous game's last boss as the last boss again (ZUN's Gaiden Game last bosses had usually been last bosses or secret bosses beforehand, and both ZUN and Tasofro had released games with the Three Fairies as the last boss on the same day, but Tasofro hadn't done the same), not to mention their first fan game based on a highly obscure title (unlike the big names Mario and Mega Man). Nitori was also another fairly odd choice of protagonist (Tasofro themselves had given her some pretty nasty Character Development in Hopeless Masquerade).
Ten Desires is the first appearance of a former last boss as a Starter Villain as well as, in the pattern started above, a similar structure to Embodiment of Scarlet Devil. A big, scary Starter Villain, then a Breather Boss detached from the rest, then a Chinese gatekeeper, then a devious magician, then a Dragon with an Agenda, then a very royal, imperial last boss. The Bonus Boss is also unusually hostile to the main bosses.
In between, the Fighting Game spinoff Hisoutensoku was a Gaiden Game to the previous fighting game, featuring weaker characters for the first time and reversing Alice's Butt-Monkey status as well as including many Non Playable Character bosses.
Fairy Wars was ZUN's first use of a weak main character and a Fallen Hero Bonus Boss as well as the first arrival of manga generations into the games, not to mention a very Unexpected Gameplay Change. At the same time, New Super Marisa Land also used the second and third of the above while leaving weak bosses to defend the worlds.
In Hopeless Masquerade, her approach became more apparent. Reimu's role was suddenly downplayed and the importance of the Villain Protagonist scenario emphasized, as well as Twilight Frontier finally giving stage 3 bosses respect and using a Triple Boss as the True Final Boss of the Villain Protagonist scenario.
The pattern of UFO and TD also continues in DDC where there are heavy parallels to PCB: the same choices of Player Character (one of whom had been gone for years), a trek across Gensokyo over the first three stages rather than a straight journey to the bads' lair, a flight into the sky in stage 4 to face multiple musical bosses, a final base containing the final stage inside but not entered until stage 5, and The Reveal that the incident is a much bigger threat than was initially apparent.
These changes may seem insignificant in and of themselves, but keep in mind how well they fit in with Seija's plans and it makes perfect sense.