Okay. I have two answers for this question my kitten.
1) if your talking about the castle in Castle Town. In that room is the kitty who has amazing save powers ( I wish I could do that) and only one way out. Go out there, go down the hall and in a room, the zombie soldier guys will come to try and attack you. Guess who comes to save the day? It's Fluffy and Jaken! Folow Fluffy into the room that he's going to. He will ask you to take him to the Tower. (Where Naraku is) Mew! Also, Sesshomaru will follow you like the way Inuyasha does. Check out his stats! Fluffy's a level 30!!!!

2) If you got seperated in the Wolf Forest. And Kagura thinks your Utsugi. Just play along. As you walk around the castle, you'll find a courtyard with a crystal, a new incarnation, Kanna, and a mute Kohaku. Play on through to the Field of Ignorance, (is it field or field?) and soon you will come back to Naraku's Manor, and you'll see Inuyasha and Fluffy! Again!!!! GOOO FLUFFY! Meow!