25-10 is a good place to get normal scrolls, and leveling up for several mercs.  Need 6 horseshoes for hard mode.  Sometimes Angelica fails to land critical, and won't be able to one-shot the boss.  This formation is tuned for clearing as fast as possible, but you can replace Zakan, Chalkle, and Eunrang with other mercs who you want to level up.

1. ★6 Eunrang+9 (Kill 2)
2. ★6 Veronia+9
3. ★6 Angelica+3 (Kill 4)
4. ★6 Denarisa+9
5. ★6 Zakan+9 (Kill 1 by counter)
6. ★6 Chalkle+9 (Kill 3 by counter)

New version.  This is faster and has more free spots.

1. ★6 Corette+3 (Kill 1, 2, 3)
2. ★6 Veronia+9
3. ★6 Angelica+6 (Kill 4)