Glad you're enjoying the game so far!
The boss will cause debuffs for each part of Hanaja that is in the Magical TF. It helps to go into the fight as a full demon (her default form) and try to keep her from transforming.
As for status effects, there are hover-over tool tips! Just hover over the icons above an enemy or hover over Hanaja's health bar to see what they are and what the effects are.