There are characters/creatures out there that
do hunt Veilbeasts and other horrors, some that even survive off them as a source of sustenance
(refer to IC page 1). The majority of characters who do hunt such creatures aren't anywhere near as strong as Kaslin, but they possess vasts amounts of knowledge and experience which set them apart from other, more powerful warriors in the world. Namely knowledge of cures to various curses, and entire profile summaries of their quarry. They're well versed in the different features of the specific tainted regions they hunt, and defeat their enemies with their preparedness, skills, and bringing the right tools to the fight which are required to kill their otherworldly enemies.
If you want to see an example of such a character, you can read further back in the game to some of the exploits of the Harrier Captain, Iron Hawk. During her and Asiresh's prison break she slayed a named Veilbeast, and later during a different event, led an attack and defeated Stella Astral (forg99rules main character). She's only 4th level, with about 8 Harrier potentials, relying mostly on mundane equipment and blitz tactics to strike hard and fast. While far weaker than miss Crowe, she's a more efficient combatant versus a larger range of tainted creatures, as Kaslin only excels at dealing with one particular type of enemy. Thus, it's less of a matter of mechanical power, and more one of knowledge and experience. If you don't know how to deal with certain creatures or survive their lairs, you won't be doing much hunting of them regardless of how hard you might hit. At least in terms of First World characters, but we haven't gotten to that yet.