I just played a game as a Shaman against a Mage and something strange happened with Devolve on a board of 3 enemy minions. The minions were Devolved into 2 Wisps and a Master Swordsmith. One of the Wisps ended up dying but the other and the Master Swordsmith were left on the board long enough for the other Wisp to get buffed to a 4/1. At this point, I Devolved again and to my surprise, the 4/1 Wisp remained a 4/1 Wisp. Obviously a 0 cost minion cannot be Devolved any lower but should the 4/1 Wisp have been Devolved into another 0 cost Wisp that is 1/1? I won the game so it didn't really matter in the end I just thought it was weird and had never seen a minion be Devolved and not "reset".
If the minion cannot transform into anything else (for example trying to evolve a molten giant or devolving a wisp) it will instead stay unchanged, keeping all buffs and/or damage.
Related to the post, i can't undestand why an Arcane Giant summoned with 0 cost (still not tried against this card with 1 or more cost) is unaffected by Devolve, like a Wisp who original cost is indeed 0. If i evolve my Thing from Below summoned with 0 cost he still evolve into 7 mana minion...
The arcane giant on the board is a 12-mana minion, although he has been played for zero. It cannot be devolved or evolved as there are no 11 or 13 mana minions. Thing from Below is a 6 mana minion although played for 0 and can be (d)evolved to a 5 or 8 mana minion. I get your logic that as a zero mana minion as played they can't be devolved, but on board they are there full cost. They are affected by a debuff in mana in your hand, minions returned to your hand which you played with a discount from emperor thaurissan will also be the full cost when returned. A wisp can get evolved to a 1 mana minion, but not to something lower as a zero mana minion. The weirdest interaction in this retrospect is for me with summoning stone/Atiesh from Medivh the Guardian. Where a spell reduced in mana cost summons a minion of that reduced cost. But even there you can argue that spells are different than minions, as they aren't on the board.
I just played a game as a Shaman against a Mage and something strange happened with Devolve on a board of 3 enemy minions. The minions were Devolved into 2 Wisps and a Master Swordsmith. One of the Wisps ended up dying but the other and the Master Swordsmith were left on the board long enough for the other Wisp to get buffed to a 4/1. At this point, I Devolved again and to my surprise, the 4/1 Wisp remained a 4/1 Wisp. Obviously a 0 cost minion cannot be Devolved any lower but should the 4/1 Wisp have been Devolved into another 0 cost Wisp that is 1/1? I won the game so it didn't really matter in the end I just thought it was weird and had never seen a minion be Devolved and not "reset".
If the minion cannot transform into anything else (for example trying to evolve a molten giant or devolving a wisp) it will instead stay unchanged, keeping all buffs and/or damage.
-EXODIAAAA!
"What have you got there,
PinocchioMalygos?"Seem's like you didn't see this match
http://www.hearthpwn.com/forums/hearthstone-general/general-discussion/179188-what-happens-to-0-cost-minions-that-get-devolved
http://www.hearthpwn.com/forums/hearthstone-general/card-discussion/191377-potential-bug-devolve-versus-0-cost-minions
http://www.hearthpwn.com/forums/hearthstone-general/card-discussion/194632-devolve-giants-interaction-not-working-the-way-it