Ultimate Mission Stories / 極限任務ストーリーズ are a kind of Ultimate Mission. As you might expect, it has a story to go along with its stages. They can be reached from the Subjugation / 討伐 button on the left-hand menu, then the Special / スペシャル tab.
At least for the first stages introduced, the stages go in this order from top-to-bottom.
- Chapter 4: Purple focuses on Magic. Drops 20/100 y/o Magic Manyus. Presumably would sometimes drop ampules of any type.
- Chapter 3: Yellow focuses on Pierce. Drops 20/100 y/o Pierce Manyus and sometimes Defense ampules.
- Chapter 2: Blue focuses on Blunt. Drops 20/100 y/o Blunt Manyus and sometimes Life ampules.
- Chapter 1: Red focuses on Slash. Drops 20/100 y/o Slash Manyus and sometimes Attack ampules.
Farming these stages can be done with one team with an absurd speed and killing power, the default partner, and all the other teams at under about 200 speed. With the fast team plowing through to the goal and the helper just following along, the other teams will never get into a fight and will try to grab chests you couldn't get along the way to the goal. The last chest past the random movement panel near the goal only contains one Life Crystal, so don't feel bad if you miss it.