As mentioned at 3:03, amputation was a punishment for crimes and so was thought to constitute a moral stain. That's why it is surprising the Chang Ji that Royal Nag can have "a complete mind in a deformed body." (Incidentally, the phrase translated "complete mind" here was "made-up mind" in 2:04.) It is interesting to note that, in addition to being physically a-typical, Royal Nag also employs what we would consider to be a progressive teaching style.