Chosen of Elune is a bad design. It would be either an extremely overpowered (full crystals) or very very shitty (empty crystals) card.
Empty crystals version: You play the Chosen of Elune.
Opponents turn, he starts with 10 crystals filled at the beginning of turn. He plays a big minion (Ragnaros, for example) and kills your Chosen (mage pings him, rogue kills him with his weapon etc.)
But the Ironbeak Owl costs 3 mana, so reducing it's attack by 1 and adding a draw a card effect would make its mana cost 4, not 2 as your card. If you consider making it a class card, you still can't reduce it's cost by 2 mana.
Unfortunately, this card is overpowered as hell - it will give you +15 health and for that time you gain an ability to create 3/3 divine shield + taunt minions as CriticalGreek wrote above...
Also, if you want to kill him, you need at least two minions to kill one divine shield taunt token to be able to reach him.
Also, if he remains a minion (so it will trigger deathrattle), you can buff him with Blessing of Kings making your hero able to attack each turn?
Chosen of Elune is WAAAAAAAYYYYYYYYYYY overpowered.
Turn 1. Chosen of Elune (gain 10 mana crystals) - Ragnaros the Firelord (or any other high cost minion) - kill Chosen of Elune with Living Roots (your opponent will start with 1 mana crystal)
Berzerker Rage (2 mana) then => Bash some minion (2 mana, you gain 3 armor so you have 30 life and 3 armor) + Southsea Deckhand (0 mana) + Arcanite Reaper (4 mana) + Bloodsail Cultist (2 mana - weapon becomes 6/3 thanks to Southsea Deckhand) + Upgrade! x2 (0 mana) (Weapon is 8/5) then attack head for 8x4 = 32 damage. You survive with 1 life.
8 mana used total
Edit1: (added rarity icon to card, edited card links and corrected the combo)
3
Chosen of Elune is a bad design. It would be either an extremely overpowered (full crystals) or very very shitty (empty crystals) card.
Empty crystals version: You play the Chosen of Elune.
Opponents turn, he starts with 10 crystals filled at the beginning of turn. He plays a big minion (Ragnaros, for example) and kills your Chosen (mage pings him, rogue kills him with his weapon etc.)
It's your turn, you gain 1 mana crystal.
0
But the Ironbeak Owl costs 3 mana, so reducing it's attack by 1 and adding a draw a card effect would make its mana cost 4, not 2 as your card. If you consider making it a class card, you still can't reduce it's cost by 2 mana.
0
Unfortunately, this card is overpowered as hell - it will give you +15 health and for that time you gain an ability to create 3/3 divine shield + taunt minions as CriticalGreek wrote above...
Also, if you want to kill him, you need at least two minions to kill one divine shield taunt token to be able to reach him.
Also, if he remains a minion (so it will trigger deathrattle), you can buff him with Blessing of Kings making your hero able to attack each turn?
6
Chosen of Elune is WAAAAAAAYYYYYYYYYYY overpowered.
Turn 1. Chosen of Elune (gain 10 mana crystals) - Ragnaros the Firelord (or any other high cost minion) - kill Chosen of Elune with Living Roots (your opponent will start with 1 mana crystal)
Also Purifier is OP, compare it to Ironbeak Owl
0
1
1
0
All spells discounted for 1 mana by Emperor Thaurissan
Berzerker Rage (2 mana) then => Bash some minion (2 mana, you gain 3 armor so you have 30 life and 3 armor) + Southsea Deckhand (0 mana) + Arcanite Reaper (4 mana) + Bloodsail Cultist (2 mana - weapon becomes 6/3 thanks to Southsea Deckhand) + Upgrade! x2 (0 mana) (Weapon is 8/5) then attack head for 8x4 = 32 damage. You survive with 1 life.
8 mana used total
Edit1: (added rarity icon to card, edited card links and corrected the combo)
Edit2: moved card to imgur