Dalkiel

Dalkiel - Angel of Hell, ruler of Sheol, and equated with Rugziel (q.v.).  In Baraita de Massachet Gehinnom, Dalkiel operates in the 7th compartment of the underworld, "punishing 10 nations," and serving under orders of Duma(h), who is the angel of the stillness of death.  [See writings of Joseph Gikatilla ben Abraham (1248-1305).]  (a)

Rugziel - an angel who operates in the 7th compartment of Hell in the "punishment of 10 nations." [Rf. Baraita de Massechet Gehinnom.]  (a)

Technically speaking Dalkiel is not fallen, at least not in this source but he is an angel of Hell so I included him here.

(a) "The Dictionary of Angels" by Gustav Davidson, © 1967