Forum:Any chance that lesser units will get future evolutions?

Just curious about this, but is there any chance that lesser units, like the Treant, Angle, and Skeleton get 4/5 stars and above later on? So far, I have them at Azrael (3rd evo for angel) Xipe Totec (4 star unit evo from Treent) and Skull Lord (3 star unit evo from Skeleton)