If you're looking for this mobs you need to kill gahaz bandit in order for it to spawn.It can spawn anywhere inside the gahaz area (so the maps here is not relevant anymore,since the 28 september 2022). It didnt spawn naturally since 28 september 2022 patchnote (https://www.naeu.playblackdesert.com/en-US/News/Detail?groupContentNo=3987&countryType=en-US#Monster) (view screenshot for the sum up of this info).
The spawn rate is random and around 10min (sometime it even take 20+min or less than a min), notified by a red message located a bit higher than the default stamina bar.

Me and a friend hunted it for S grade (with ~150% more knowledge and ~35% higher grade) it took me 5 kill in order to get S and my friend took ~35kill to get S grade.

If you have a friend that is OK to help you he can spawn the boss on another of your guild channel and you switch channel to kill it in order to maybe get the knowledge. That what we did and it took us an entire afternoon.

NB:Prior to this patch note those monstrers spawned naturally (as the map is showing) which was a bit easier in order to get knowledge.