The easiest way to beat Demon Inuyasha with Sesshomaru is to get his hp lower than yours (try to use the miasma to your advantage by always running around it but makin him run through it)then for the rest of the match run away from (just run in big circles) and make sure you don't get hit(try to have a big gap between your health and his just in case you get hit my him or miasma) trust me this is the easiest way to beat him and best of all it only takes a minute and while using this tip you
get to see how cool Sesshomaru is
Hint: Fight Around Black Pearl
You can only fight around Black Pearl using Sesshomaru or Koga only -- the other characters cannot do this. Your oppenent must be on the edge of the battle field of Black Pearl before you jump down from the battle field. After the bird drops you back into the arena, jump up and use a fast attack (default on the X key) and you should land outside the Black Pearl. Have fun fighting and watchout for holes.