The ones fighting for Ukraine are part of a Salafist network. They're extremely radical. They want to ethnically cleanse all ethnic Russians from the ENTIRE Caucasus and form a full on ISIS tier Caliphate from coast to coast. They even support the death penalty (I'm not joking) for women who go out of the house without a Burqa. They support terrorism in Russia (subway bombings etc) to achieve their caliphate.

Like I said, some of their leadership helped organize Beslan.