If Orcus had been an Intermediate god, there was no way Kiaransalee, that uppity little demipower, would ever have managed to kill him in the first place.
As it is, if WotC were willing to give Orcus his due, things would be getting interesting, since Lolth's Silence has caused Kiaransalee to experience an influx of worship that's since bumped her up to a Lesser deity (which is Orcus's divine level..presuming he has one).
And you just know there would be a reckoning; Kiaransalee calls her realm in the Demonweb Thanatos, having named it after the place she took from Orcus.