God-level Hero - Chapter 168 - 161 Reward from the Resented Elfs Heart_3

Frank, a mercenary known for his cold ruthlessness, decides it’s time to leave the bloody world of the underworld behind. But the underworld has no plans of letting him go. Relentless enemies from his violent past keep hunting him, and eventually, they succeed—Frank is killed.But fate has other plans. Instead of staying dead, he is mysteriously reincarnated into the body of a cop in a world filled with crime, corruption, and dark secrets. With the help of a strange, all-knowing system, Frank is given the chance to live again—this time, to prevent crime before it happens.

My childhood friend went to the academy.

Because I like to collect antiques, I was accidentally brought to a magical world by a crystal skull in my collection.

- Description from novelbuddy

What would you say is the most valuable thing in this world?