Then the player would be required to begin killing that monster again in the hope of achieving a better rank. Prior to the 10 January 2018 patch, to improve knowledge rank of a specific monster required the player to visit the Annolisa Rosie and pay 10 energy to delete the current knowledge of that creature.
A+ - Gives +7 AP bonus against the monster.A - Gives +5 AP bonus against the monster.B – Gives a defense bonus against the monster.C – Allows the player to see the target monster's HP.
It may take multiple kills of the same type of creature before the knowledge is acquired. Knowledge rank is the level of knowledge acquired by killing NPC mobs.
