You have to consider that Otyugh (the main "Devour" creature) costs 4 and is a 0|3 with only +1|+1 bonus (and is yet one of the best creatures in the game).
Both of them are overpowered...
As said, adding +2 to defence on devour is really overpowered (couse really soon you will devour ALL creatures played by the opponent).
Both of them need to be much more expansive, or they just have to gain +1|+1 (And still be great, couse they will be as improved Otyugh, that I dunno if it's a good idea, couse it will make Oty about useless).