I draw my bat boy character Kuraresu and another bat boy character Wolken with simple green background and I draw this art in around 2008. in that time I don't draw the arts much but I scribble many simple characters to change my coloring way and the mood, and their pants is different. when I draw this art I think to draw a new bat character and the deep gray bat character come out, but I feel he looks like a wolf and I forget this art, after in 2020 I start to draw the goblin boy characters and I feel they need a warg character and I just recall this wolf like bat character, in 2022 version I add the white color and his appearance is different and I decide he have both wolf and bat feature.