I think the best way to do it is to have him come out to the ring one day in his jacket telling the world about his self. Saying that Rosa is his new girl (kayfabe.) He said and it's time he stopped living a lie. He say's I am not Adam Rose....My name is Leo Kruger.
He would then take off the jacket revealing he has his Leo Kruger gear on. He say's and it's time to stop dancing and time to be ruthless.
I would have him go vanish from TV shortly afterward and then return out of the blue 3 months later. No video packages or nothing. Someone calls an open challenge and he comes right out to accept. He beats the person ruthlessly and the match never get's started. The person is stretchered out and he continues to take people out in that manner for a while.
Then you can have a upper-mid card face like Ziggler stand up to him and fall short in the feud and is stretchered out. He can then have a feud over the Intercontinental Championship or US Title with a face like Neville or Cena beating them and they get stretchered out.
I would have him dominate the RR before being eliminated by Randy Orton. The next night following Orton's match the lights go off and on the titantron we see a message saying "Warning" in red letters blinking with a warning sound (maybe the type of sound the play for tornado warning alerts on the news.) Before it say's "You've been warned."
The light's come on and Kruger decks him with a huge clothesline and hits a finisher before using Orton's punt kick on him taking him out.
This would set up a Mania feud over the IC/US title. Kruger goes over and then moves on to feud with a newly turned babyface Wyatt (who just beat Triple H at Mania) winning the first time,before losing the title at Payback and losing the rematch at EC.
Kruger would go on to win MITB and BOOM you have created a star.
This is HIGHLY unlikely but would definitely work. Also for it to work he would need to put on the same weight he had as Kruger in NXT.
Besides anything is better than playing the role of a drunk off their ass Willy Wonka reject in a domestic violence relationship with a bunny.