A parody of different battle monster series. The idea is that basically if the kid(s) in these series were actually traveling around battling animals/monsters in real life, they'd pretty much be vagabonds or bums having animal fights. The situations in this comic aren't anymore realistic than any of the titles it's poking fun at, but the element of the wanderer is brought in more.
That being stated, the artist is a huge fan of every battle monster manga, anime, or game there is and it's all meant to be taken very lightly.