If you have find troubling to defeat monster, try using these:
1. Get a Map Selector
2. Get a place where there are many status items
The status item is unlimited you can get them as many you want, until thyre max.
Get Super Hard Difficulty Level
Beat the game using Hard Difficulty
Unlock "Liv Special PV", "Total Results" and "Extra Menu" options
Beat the game using any Difficulty level
Play Previously Played Levels
On stage 9 beat the boss and you will get the Map Selector which allows you to go to any completed level
Change Enemies on Previously Played Levels
Beat the boss on level 10 to unlock Change Appearance which changes enemies on replayed levels
Destroy the final summon
Slash twice then us the upper cut then summon up the 2nd summon monster it will die!