The monsters along the way were very weak. Their level was only around 30; they were nothing to Tan, and of course, there was no increase in their level.
However, they were just monsters along the way. When they reached the foot of Rodenhill, which was the entrance to Cadas Cave, the monsters’ level immediately rose to 70.
“It’s getting harder,” Tan said after the battle had ended, which helped Edward and Lin to rise to level 34 and 39 respectively. At the time of his arrival in Calip, Edward was at level 38, but he lost his life to protect a girl he flirted with while waiting for Tan, which resulted in him losing five levels.