The next Adventure for Blizzard's collectable card game, Hearthstone: Heroes of Warcraft is out tomorrow. Titled One Night in Karazhan, the Adventure will transport players to an age where Karazhan was lively and filled with fun. Despite being set in the past, the expansion's experience will be inspired by the raid of the same name in World of Warcraft. To find out more about One Night in Karazhan, we chatted to producer Yong Woo and lead designer Ben Brode. Here's what we learned.

Karazhan Was Supposed To Be the First Hearthstone Adventure

Brode: We were thinking about doing Karazhan as our first adventure. When we were trying to figure out what to do first, we designed 30 cards for Naxxramas, and 30 cards for Karazhan. We had others we were considering as well. We almost went with Karazhan as our first Adventure. Naxxramas barely edged it out.

We had actually decided not to do Karazhan for this Adventure because so many other teams were exploring it… we didn't want to have too many different versions of this that are slightly similar. When we decided to focus on the idea that this is an arch-mage's tower… things are enchanted and there's wonder, mystery, and fun here, it felt like a different enough take on Karazhan. That it wouldn't be mixed up with other versions of Karazhan that are happening at the same time.

Woo: There's so many people on the team who love, love Karazhan. I think we just wore people out! I've been begging to do Karazhan since Naxxramas. Coincidentally, there's a lot of Karazhan-related content happening across Blizzard at the same time. It might not be as co-ordinated from inception that people might think it is… it's not like we have a big company-wide meeting where we say, "Okay, 2016 is going to be the year of Karazhan."'

Blizzard Acknowledges The Priest Class Struggle

Woo: That's a topic that's really near and dear to my heart, because I main priest in Hearthstone. On one hand, as a priest player I embrace the underdog status. I think it's cool that there are players out there that also main priest and set themselves it as a challenge to get to Legend every month. It's a challenge that players can set for themselves and I think that's cool.

In terms of, are we going to fix the priest power standing right now… there are a couple of things to consider here. One of them is, when you look at what the power level of a class is going to be, you can't just look at what new cards the class is getting. But right now we're getting One Night in Karazhan… the meta itself is going to shift. And at that point, it's not just the cards that priest is getting is important, what's going to be important is what deck ends up becoming dominant in the meta in general. And will there be a spot in that meta for priest.

There's definitely a lot of exciting cards that I'm excited about as a priest player, that we're getting into the mix with Karazhan. I don't think we say in this interview right now, yes, there is this card and it's going to propel priest to number one world championship deck, but there are a lot of really cool and fun priest cards coming out. Let's see how the meta plays out.

Brode: One of the things that we do is that we try not to give powerful cards to archetypes that are already the strongest. Because if we want the meta to change--which is the goal of releasing new content--we want new decks to arrive, sometimes we give tools to decks that are close to top tier, but need a little extra juice.

Priest is one of those classes that I think can be very strong depending on what the meta is like. We're adding some cards that could support some archetypes that traditionally have been strong in priest. Dragon priest is very close to being quite strong, I think. And we're adding some new cards for that archetype. Bookworm, for example, I think is a good card for Dragon Priest.

Woo: I think it's really important for me that players know that we really care about priest. For someone like me, personally, I really care about priest, I play priest every day. I have fun playing priest even though it can be challenging sometimes.

I don't think this is the type of thing where we print a bunch of OP cards and suddenly we're in a better place. We need to remember that priest has been in the past, and has potential to be, the most hated class in the game. It's something that we need to consider carefully, and continue to introduce fun and new archetypes for priest and explore that. But this is something we need to do with big consideration.

Eleven of the Bosses Are From the Wow Raid

Brode: It is such an iconic raid experience. And we wanted to make sure that for fans of the raid, this felt very familiar. So 11 of the bosses in One Night in Karazhan are bosses from the World of Warcraft raiding experience. A lot of the collectible cards are things you remember from that experience.

Moroes is the host of the adventure, because Medivh is missing and he leads you through the tower, opera house, menagerie, through Medivh's quarters at the top of the tower to find Medivh and save the party. I think there will be lots of references and iconic boss battles.

Netherspite, one of the most fun battles in World of Warcraft's Karazhan. Everyone remembers those beams. Translating that for Hearthstone was a ton of fun. Those beams come from the portal and hit Netherspite, but you can put minions in the way to make sure those beams are empowering your minions instead. If you don't that right, the beams will hit Netherspite and he'll get the buffs. And just like in the World of Warcraft, that could be a disaster.

Why You Can't Pre-Order One Night in Karazhan

Brode: Creating a patch is logistically challenging given how many platforms we operate on. Given the small window of time between announcement and launch, getting a patch ready, getting it approved,and then doing it again two weeks later, it's a logistically challenging thing that we weren't sure was worth it this time. We still have a bonus for purchasing the entire adventure before all the wings come out, so it feels a little bit like a pre-order.

We didn't do a pre-order bonus for League of Explorers either, for a similar reason.

Woo: You know what, it's so funny because as a producer generally the instinct is "Let's build stuff, let's use this valuable engineering time and our time to build a system, and then let's use it again." Why not?

Mixing things up and keeping the players guessing is a huge part of our team's culture and even one of our core tenets, delivering delightful surprise. Even our business model, we keep trying different things and mixing things up. So this time around, we've giving incentive to purchase all of the wings during the first week. We'll try this out and see how the players like it.

Summoning Prince Malchezaar From An Unstable Portal Won't End the Universe

Woo: Thanks to advanced goblin and gnome technology, we're able to close the time loop...

(laughs) Obviously, the ability cannot trigger from unstable portal.