'I can't investigate it now,' thought Arthur.
He knew the limits of his strength, even if he had the skills to infiltrate underground, trying to force his way into it would only get him in trouble.
Despite the unknown threat, he had no doubt about leaving there.
In situations like this, he would return to his main philosophy. Whatever it is, it can be resolved when you become stronger.
On his way back, he picked up every Eternal Cave Mushroom that grew. There were five of them. If used properly, not to mention women like Carla, Bella, and Amanda, even the tigers and harpies could possibly become spiritual creatures.
Quickly, he arrived at the mouth of the cave again.
He didn't explore other tunnels because they were connected to the largest one.
By the time he got there, Isabel was still fighting the bears. They seemed to be skilled enough in combat that Isabel, who was still a rookie, had little trouble despite the fact that she was a Magus.