Board Thread:Questions and Answers/@comment-29752445-20170415172945/@comment-1327106-20170416233506

CommonSwift wrote: 2) Kenny didn't want Rod to have other children so he could have a better shot to take the power for himself.

I suspect it's more this than anything else. Alma had been alive and shoved off to the side for years, so there was little incentive to kill for her an indiscretion made years ago. But circumstances changed when Rod ran off to the scraps of his family left after his legitimate one was killed.

Kenny was prepared to kill both Historia and Alma, and we know Kenny actually doesn't care jack squat about Rod or even what his job is supposed to be. He was Uri's friend and wanted the power that might make him a better person.

Letting Rod get Historia back and rekindle a relationship with Alma would threaten the sweet fortune Grisha's rampage gave him (since Kenny didn't know the bloodline was a requirement).

I very much doubt that Kenny killed Alma under anyone's orders and Rod doesn't seem to have enough of a spine to have stood up to him.