In the manga it is Kanna who tells Moryomaru where to find Ginka and Kinka. IY does not really want to bother them, but they keep fighting each other and endangering everyone. Moryomaru comes to absorb them but though they were tied together and forever fighting they would turn on anyone who fought against them. In the end they both die but Moryomaru is only able to absorb Ginka while Kinka allows himself to be absorbed into Tessaiga In the end the brothers are separated, IY apologizes to Kinka for involving them. Kinka accepts so long as IY kills Moryomaru. The whole episode shows just how Naraku is playing games with IY and Moryomaru. The anime gave Sesshoumaru something to do in this episode which he lacks in the manga. The Yoreitaisei episode is triggered by a failure to kill a monster which Sesshoumaru kills easily after which he tells IY that he does not understand Tessaiga at all and is making it harder to attack things by absorbing powers with Dragon scale Tessaiga. Next week is the death of Moryomaru 11/14 Mt. Azusa 11/21 the death of Kikyou. The hell arc occurs after the death of Kikyou.