Just a little thought I had.... Since fighting is the only way to earn money, some players really struggle to get past Student Rank. I myself know this from experience(I SHOULD have over 1200 EXP right now, but I only have 809 thanks to so many losses.). But, this little idea won't allow rank ups, just money. Note, only certain Ranks can perform a certain Mission...
D Rank: Capture Satan's, er... Tora the Cat
Summary: The Daiyamo's Wife's Cat has escaped... Again. Subdue it and bring it back.
Payoff: 15 to 25 Yen.
Requirements: Defeat the Opponents within the Time Limit.
Opponents....
Stray Cat 1: HP: 75, Speed: Normal
Stray Cat 2: HP: 120, Speed: Slow
Tora the Cat: HP: 100, Speed: Fast
Claws: The cat's meow. *Shot* Ow... Does 10 Damage, and causes Blindness. (2 Chakra)
Hairball: Do I need to go into detail? Does 10 Damage, and Causes Slowing. (2 Chakra)
Headbutt: It jumps head-first in a collision course with your stomach. Causes 10 Damage and Screwed Controls. (2 Chakra)
Hiss: The cat gets mad and goes into a brief frenzy, making it's attacks much harder. They all do 15 damage in this state, and the Cat gets a speed boost.(4 Chakra)
Time Limit: 3 to 4 Minutes.
Other ranked missions to come to this suggestion.... When I think of them... ^^;