The phrase "to slay the beast" means to defeat or overcome a difficult or challenging problem or situation. It can be used metaphorically to describe conquering fears or obstacles. Full definition
Generally regarded as the ultimate title for «grinding,» the core gameplay loop consists of slaying beasts for upgrades, to move forward to the next. (windowscentral.com)
On a quest to find the one girl who's willing to join me in slaying the beast that is life. (otakusingles.com)
It's not surprising to find, then, in the voluminous behind - the - scenes footage from the documentary «Richard Linklater: Dream Is Destiny,» that on set he comes across more like a gatherer than a hunter, as if making a film isn't about slaying some beast but harvesting the small riches in one's environment. (latimes.com)