My assumption was wrong. It's partially explained in the next chapters.
ch 16 First to Kill a Wild Boss, Full-Service Announcement!
Sci-fi · Ultimate Guaiguaipi
I think he's the first solo player who killed a wildboss. Other wildbosses were killed by guilds and counted as a group achievement.
ch 16 First to Kill a Wild Boss, Full-Service Announcement!
Sci-fi · Ultimate Guaiguaipi
See this! I just gifted the story: Lollipop
ch 361 361. Guests Incoming
Fantasy · 1King_Rep1
See this! I just gifted the story: Inspiration capsule
ch 1278 1278. To Be A Healer (1)
Master of none
Fantasy · 1King_Rep1