From Destinypedia, the Destiny wiki
Deserter Legionaries are Cabal Honored Legionary's who deserted from the Red Legion. They can be observed in The Arms Dealer strike and a few of its respective Reduxes. From title, they are apart of the Cabal Deserters.
Deserter Legionaries remain the same as regular Red Legion Legionary's apart from name-change and being Elite variants.
List of appearances