They have a flaming disc in each of their hands which they use like Yo-Yo's to attack Dante.
They can be killed the same way as Marionettes but take a longer period of time. Ifrit in devil trigger mode can take down these devils in no time at all.
Nelo Angelo can be fought with virtually all weapons but the weapon of choice would be Alastor or Ifrit.
Kyklops should be approached in the same way as Phantom and attacked on the mouth or tail. They have less armor and take less time to kill.