What Touhou Project character's first ever appearance was as a midboss in the eighth game, Imperishable Night?

The answer is Tewi Inaba because she first appeared as a midboss in the eighth game of the Touhou Project series, Imperishable Night. Tewi Inaba is a mischievous rabbit yokai who is known for her ability to manipulate luck and fortune. As a midboss, she poses a moderate challenge to the player during gameplay, showcasing her mischievous nature and her place within the vibrant and fantastical world of Touhou Project.