The visual effects during her spell cards are dizzying and highly atmospheric. đź’° The Infamous "Kei Kei Kei" Loan System
“Never again.”
Reimu’s crimson bow untied itself and re-tied into a sharp, businesslike cravat. Her miko dress shimmered, becoming a severe black suit with pinstripes that squirmed like tiny serpents. Her gohei—her purification rod—cracked and reformed into a metallic ledger book with brass clasps.
In a climactic confrontation, Marisa reached Reimu just as she was about to finalize a massive loan of spiritual energy, which would have sealed the fate of Gensokyo. The brainwashed Reimu, with her eyes glazed over, uttered one final, commanding "Kei Kei Kei."
However, based on the individual components of your query, here is the relevant context: