Fenrir wasn't sure how much time had passed, as the days seemed much longer than normal here, but she had watched the sun and moon trade places in the sky seven times since her arrival. In that time, she had hunted down nearly a hundred of the giant monsters located around this forest, many ranging between 8m and 15m in height. Fenrir noticed that there were distinct differences in the quality and strength of each monster but, even the giant monkey she fought hadn't been much of a challenge.
The monkey had been covered with metallic silver fur and had four eyes that burned like hot coals on its head. Because it had been living at the top of a mountain, where no other monsters had lived, Fenrir thought it was something like the 'king' of this area. However, as big as it was, Fenrir managed to get a quick advantage when she severed its leg during their first exchange. Though it tried to counter-attack by shooting a strange energy beam from its mouth, Fenrir used her instant movement technique to easily evade it before burying her claws deeeeeep into its head.
Since she had already killed so many monsters, Fenrir realized that the cores were almost always located at the front of their brains or near their hearts. Since the monkey monster had a big forehead, which seemed to be covered in extremely durable hide, Fenrir assumed its core would be located there. At the very least, she would be able to disorient it by shredded up part of its brain with her claws. Fortunately, she had been saved the trouble since there was a grapefruit-sized core at the front of its brain. Its thick skull might have protected it from other people, but Fenrir's claws were able to cut through almost anything, even things that were supposed to be 'Indestructible' in nature.
Without a core, the monkey monster immediately keeled over, dropping to the ground with a loud thud as it slid down the mountain a few meters. Fenrir chomped down on its core while lazily making her way over to the corpse, proceeding to slice it open like a surgeon and remove the 'good' parts. She had learned that it was a waste of time to eat the entire monster and that there were only a few delicious parts that had a lot of energy inside of them. With this in mind, Fenrir harvested some of the larger bones, most of the monster's organs, and, most importantly, its heart. Other than the monster core itself, the heart contained the greatest amount of energy and Fenrir found the flavor to be rather sweet and tasty.
After eating her fill, Fenrir went into the cave where the monkey had previously resided. She was surprised to find the remains of several human-like creatures strewn about all over the cave. Some of the bones even had a slightly metallic sheen to them and, after investigating, Fenrir deduced they were full of the same energy as the monsters. However, as they looked very human-like, Fenrir decided to bury them all in a small grave. Even if they possessed a lot of energy, Fenrir didn't think her Master would have appreciated her eating the bones of a human. Since all of her friends, companions, and 'family' were also humanoid, Fenrir didn't want to become a monster just to gain strength...
(Fenrir's Commentary: 'What kind of human bones are made of metal~?')