This is more of a thought than a theory.
Remember when everyone thought Killer was going to be related to Sanji?
Well what if that's still possible? The Vinsmokes have never shown their clone Alpha's so we don't know who or where the material for the clones comes from. What if A. They attempted to make a clone of Sanji when he was young and it seemed like his powers wouldn't manifest and Kidd got him somehow. or B. They made a clone of Ichiji but for whatever reason it didn't work like the others and Killer escaped.
Would you approve or disapprove if it turned out Killer was an escaped/failed/rogue Vinsmoke clone?
Remember when everyone thought Killer was going to be related to Sanji?
Well what if that's still possible? The Vinsmokes have never shown their clone Alpha's so we don't know who or where the material for the clones comes from. What if A. They attempted to make a clone of Sanji when he was young and it seemed like his powers wouldn't manifest and Kidd got him somehow. or B. They made a clone of Ichiji but for whatever reason it didn't work like the others and Killer escaped.
Would you approve or disapprove if it turned out Killer was an escaped/failed/rogue Vinsmoke clone?