The Intuition

The experience points he gained this time were a lot less compared to when he killed the Old Fire Yak. 

Not only was it because the Old Fire Yak was two levels higher than him, this time, the experience points have also been shared by three parties, him, the beast and then the grimoire. 

As expected, if a beast was present, they would receive the most experience points. The summoner would receive a portion, while the grimoire would receive the least amount of experience points between the three. 

According to Marcel, this was because the beasts has higher experience cap compared to the summoners and grimoire, and because they were the ones who usually fight the opponent, hence the reason why they received most of the experience points gained during a battle. 

Due to the high experience cap, beasts would often level up slowly. Of course, if they were lucky and performed very well, they could also receive a direct upgrade from the World's Will.