When did Kastro dirty himself with blood? In episode 32 of Hunter x Hunter (2011), “A x Surprising x Win”, Hisoka can distinguish Kastro from his double because the original (left) had a blood stain on his chest that was not reproduced by the double-creation technique.



But when did he acquire it? I can’t find the moment in which he would have gotten the stain. It just appears when it’s convenient to the plot.
According to the manga (chapter 54), that wasn’t blood, but “grime that builds up during combat”. So in the anime it was probably a case of the animators not wanting to waste time and resources on representing that before it was needed.