Renounce Darkness

Renounce Darkness is an epic warlock spell card, from the Whispers of the Old Gods set.

Strategy
The strategy to using such a gimmicky card like Renounce Darkness is to build around the gimmick. To do this, your deck should have a lot of Warlock Class Cards in it. Start by putting the mostly of the zoo warlock cards in and just in case you end up not drawing Renounce Darkness you will still have an okay deck. Once the deck is finished, you will want to try and mulligan for it removing all 3 mana or higher cards. If you end up getting it in the mulligan, DO NOT play it until you have a total of seven or more cards in your hand, including Renounce Darkness. This is because if you play it with 4 cards you will no longer have your hero power to keep drawing you cards and you will run out of steam fairly fast. After that it is all random from there and is not predictable.

Lore
This card appears to depict a human warlock renouncing the Darkness to follow the call of the. However, since the class switched to by the spell is random (and not limited to classes which worship the Light, namely the priest and paladin), this does not appear to be accurate. The light depicted may therefore simply be representative of a return from the Darkness, or may represent the Light turning the warlock away from their former path.

The spell is distinctly original to Hearthstone, as is the concept - warlocks are rarely (if ever) known to renounce the Darkness in favour of the Light, or any other path.

Trivia

 * Renounce Darkness was designed by Peter Whalen.
 * If this card is played while Nemsy Necrofizzle is the warlock hero, she will lament that "darkness was fun".
 * If this card is played while Mecha-Jaraxxus is the warlock hero, he will say "DARKNESS DELETED!".
 * Renounce Darkness is the only collectable Holy spell outside of Priest and Paladin.

Fixed bugs

 * Prior to patch Patch 5.2.0.13619 Renounce Darkness's cost-modifying enchantment was not detached from minions that enter play (this let you also see that they have no art).


 * Prior to an unknown patch between Patch 5.0.0.12574 and Patch 7.0.0.15590 the behaviour of this card was as follows:
 * Rather than buffing all eligible cards in your deck and hand to make them cost 1 less, Renounce Darkness was coded in the following way:
 * select a non-Warlock class;
 * replace your Hero Power with the basic Hero Power of the new class;
 * replace Warlock cards in your hand with random cards of the new class, and give to each of them a "costs (1) less" enchantment (cards in your hand from other classes are left untouched);
 * replace Warlock cards in your deck with random cards of the new class;
 * create a permanent on-draw trigger attached to your player that triggers whenever you draw a card of the selected class and applies a "costs (1) less" enchantment to it.
 * This means that cards added to your hand from your deck in a non-standard way, such as Tracking or King's Elekk, do not get the cost reduction.
 * It also means that if you use Renounce Darkness as a non-Warlock and the spell chooses your current class, any of your own class cards which are subsequently drawn will be reduced in cost by 1.


 * After Patch 17.2.0.47374, Renounce Darkness was seen to be able to give upgraded Hero Powers sometimes. After the hotfix on May 14, 2020, this was fixed.

Patch changes

 * Holy spell school added.
 * Unknown patch between Patch 5.0.0.12574 and Patch 7.0.0.15590: Renounce Darkness's cost reduction effect now behaves according to its card text.
 * Added.