Roaring knight is Asriel. Roaring knight uses same attack patters as Asriel in Undertale. Roaring knight uses similar attack patters as Marisa in multiple Touhou games. Toby has been adamant in giving those Marisa bullet patterns to Asriel before and hes doing that now.

My bet is that Dess is really dead and Asriel has some retarded plan regarding resurrection. Screencap this.