Grape Guardbeast is a fairytale and a madness spirit in BLACKSOULS 2 you can find in a certain part of the Garden of the Heart area. To get to that secluded part of the garden you have to go northeast until you find a path that leads to it.
Grape Guardbeast will only be present there if you started Griffy’s storyline – this means you have to interact with Griffy at the Tenniel Bridge and the Serpent God’s Altar when she’s talking to Bill.
After those two interactions she will be at the secluded part of the Garden of the Heart, and in front of her will be the Grape Guardbeast who she cornered. You can have her help you in the fight against him and he can be quite tricky to overcome at the beginning of the game – he has 3 phases.
But once you kill him Griffy will be very thankful, and you will get the Fox and the Grapes fairytale. You will also get a kiss on the lips from Griffy.