As Saxony says in this comic, the creature in question is indeed
a Rakshasa -- a demon or evil spirit from Hindu mythology. How he can tell this on sight is
a mystery perhaps best left to sorcerers, since these creatures are known to be shapeshifters
and can appear in almost any form. The stories of Rakshasa are quite varied and they are
often malign tricksters rather than savage fighters like the one we've just met.
The Wikipedia entry on Rakshasa is a bit
sparse, but it's a place to start if you want to learn more.
- Grayson Towler