This data analysis is aimed at finding which boss was statistically the hardest boss to kill in the history of World of Warcraft when comparing guild progression data. Due to data not being accurately collected until 2008, it is very difficult to come to a concrete answer. However, with the data available, I am able to come to several conclusions and make the argument that one boss was in fact, the most difficult encounter to defeat in the history of World of Warcraft.
There are limitations to this statistical analysis. This is not a subjective analysis. Many may try to point out factors such as mechanics or relative difficulty from their experience. This is an objective analysis using data available. It may or may not be 100% accurate due to not having all the data available.
The majority of the statistics were obtain via WoWprogress.com, the premiere website for tracking boss kills.
The statistics in question are as follows:
Subscription numbers
Number of guilds that were raiding at the time.
Number of guilds progression through the instance at the time.
Number of guilds defeating the encounter when it was active.
Availability of the encounter while it was active.
Because of the nature of the data, I will also be introducing several factors to accompany my analysis. This should suffice the majority of concerns about simply looking at raw data.
Encounter tuning (Nerfs or lack thereof). Minor hotfix nerfs will not be considered.
Resources available for players at the time (Websites, kill videos, guides, split runs, lockouts)
Timing of the Raid (mid/late-expac)/Accessibility
Encounter Gating
The number of guilds raiding during this time has been tracked by WoW progress since 2009. If a guild killed a boss during the tier, the website tracked progression kills via percentages which can still be seen on the website.
One key point I'd like to make when choosing which data to analyze was what I like to call an “active” kill. An “active” kill for this research is a kill that was obtained before the release of the next content tier/pre-patch. The reason why I looked at data for “active” kills was because when a pre-patch or the next tier of raiding is released, bosses usually get nerfed and/or new gear allows guilds to kill older bosses easier than it was when presented as new content.
I was very interested in trying to find overall data for Vanilla encounters. I have heard previously that C’Thun was mathematically unkillable for several weeks. I have also heard that only 21 (or 59)s guilds defeated Kel’Thuzad during Naxx-40. However, I am unable to find any data regarding Vanilla overall kill videos. Blizzard did give out instance numbers during Blizzcon 2005. But this data is limited due to not knowing overall percentages of guilds progressing through Vanilla instances. In fact, I am only able to track guild progression starting at Tier 6 (Sunwell Plateau). Therefore, I am only able to compare encounters to which there is data which would be Sunwell Plateau and onward. I know the default answer for some is C'Thun due to being mathematically impossible. But we have to consider what data the public has access to. Secondly, we unfortunately do not have data on non-guild raiding or PUG raiding.
Throughout my research, it was very quickly revealed to me that there would be 4 bosses that would be in consideration as being the hardest bosses statistically to defeat: Kil’Jaedan (Sunwell), Lich King (25m Heroic), Mythic Blackhand, and Mythic Kil'Jaedan.
Kil’Jaeden (Sunwell)
This version of Kil’Jaeden was the final encounter in the Sunwell Plateau raid during the Burning Crusade expansion. Sunwell Plateau, along with previous tiers in the Burning Crusade, were gated via attunements. Sunwell is known throughout the community as being one of the hardest instances ever released.
Active subscriptions while this encounter was active: 10 million
Number of guilds that were killing bosses during this tier/raid: Unknown
Number of guilds defeating the encounter while active: 377
Release Date: March 25, 2008
First Kill: May 25, 2008 (62 days after release)
Last Date for active kill – October 15, 2008 (3.0 Pre-patch release date)
Availability for active kill: 204 days
The Case For:
KJ is a boss not many raiders had the opportunity to see, let alone get close at killing it. Sunwell Plateau in general was not tuned properly and Blizzard has come out and said they did not bother fixing it because WotLK was on the horizon. The numbers do not lie, only 377 guilds were able to defeat this encounter with an average subscriber base of 10 million+, there were plenty of people available to try and kill this boss. Very few even dared. It took over 2 months for SK Gaming to finally defeat Kil’Jaeden for the World First kill. Clearing Sunwell is a badge of honor most guilds would give anything for.
The Case Against:
While raiding was not as fine-tuned as it would become at the time, it was available for just under 6 months. Players seemed to have ample time to get more kills in, but it is clear that raiding wasn’t a top-priority amongst the majority of the population. It wasn’t until Wrath that raiding became the premiere content that the playerbase embraced. Competition wasn’t as relevant as it would become later on. The number of 377 guilds killing KJ can also be explained by the fact that Sunwell was a “gated” raid due to attunements. Therefore not many people we able to get until the instance, let alone go after KJ. It’s hard to say that a boss was hard if players can’t even try it out without beating the other raids before it. However, they did have 204 days to do it. We also do not have enough data on the number of guilds raiding as we would beginning in Wrath. The raiding population cannot be conclusively ascertained at the moment. Therefore comparative numbers cannot be obtained and a full disclosure of the case against Kil’Jaedan (Sunwell) is unsubstantiated.
Lich King (25-Man Heroic)
Active subscriptions while this encounter was active: 11 million
Number of guilds that were killing bosses during this tier/raid: 59,356 (25-man ICC), 84,136 (10-man ICC)
Number of guilds defeating the encounter while active: 1,101
Release Date: February 2, 2010 (Date Lich King encounter was available)
First Kill: March 26, 2010 (52 days after release)
Last Date for “active” kill – November 23, 2010 (4.0 Pre-patch release date)
Availability for active kill: 294 Days
The Case For:
Blizzard actually came out and said that more people were raiding during Wrath than at any period in the game’s history (Source Patch 5.4 Roundtable, quoted by Tom Chilton https://youtu.be/WeV5Cj7sES8). WoWprogress.com data agrees with this. The fact that this boss had more people with the opportunity to face this encounter makes this one of the toughest encounters ever simply put by how many people actually got the boss down. Relative competition and the player pool cannot be ignored. So very many people raided ICC, only 1,101 got it down on the hardest difficulty. Unlike previous raids, the Lich King would not become available until February 2, 2010, due to gating. The resources available at the time were out there, but not as pronounced as it would become towards the end of Cata/MoP-era. The most prominent resources were Elitist Jerks forums and TankSpot videos. Players were delegated to using Elitist Jerks forums for any insight regarding strategies and detailed boss kill videos were mainly provided by TankSpot.
Icecrown Citadel was nerfed 5% overall every week until it reach 30%. It was also an end-expansion raid that was out for nearly 300 days. Players had lots of time and help from Blizzard to kill this boss but many were still unsuccessful. It took 52 days before Paragon could shatter the soul of Arthas. Guilds were also impeded in their efforts by limited attempts per week on the boss. Something no other raid had ever introduced. The fact that the highest raiding population in the history of the game, coupled with the 30% nerf, proves Arthas was the more formidable foe in the history of the game. In fact, Paragon obtained the World First kill via the first 5% nerf to the encounter.
The Case Against:
Some human factors come into play in the case again Arthas. The emergence of 10-man heroic raiding saw players not even attempting 25-man raids. However, because ICC had 4 separate lockouts (10N, 10H, 25N, 25H), players were able to gear up quite significantly in preparation for the final battle with the Lich King. Other than that, I cannot find many good reasons why this fight was not the most difficult fight to kill. There’s a very strong case for The Lich King, not much against it. Players had plenty of time and ample resources to defeat the encounter.
Mythic Blackhand
Active subscriptions while this encounter was active: 7.1 million (End of Q1 2015)
Number of guilds that were killing bosses during this tier/raid: Highmaul – 41,996, Blackrock Foundry – 32,544
Number of guilds defeating the encounter while active: 717
Release Date: February 10, 2015.
First Kill: February 20, 2015 (10 Days after release)
Last date for “active” kill: June 23, 2015 (Release of Tier 18 Hellfire Citadel)
Availability for active kill: 133 Days
The Case For:
It is hard to deny that Warlord Blackhand was the very tough encounter to beat. One of the contributing factors is the sheer amount of guilds raiding at the time, the total number of active kills, and the very short availability of the encounter. Also, it wasn’t very hard to find strategies to defeat this encounter. Video guides, kill videos of other guild’s kills, and the size of the forum community providing insight was at an all-time high. The difficulty of Mythic Blackhand was so great; it can be argued that it was actually the albatross that has sent hardcore raiding into a steeper decline. This encounter broke many guilds, and for good reason. It was fucking hard. Players had ample resources to get this guy down and they couldn’t. Split-runs to gear out mains became the norm. Garrisons offered Mythic gear to any player that could kill the heroic difficulty of the raid. Players were given every chance and tools in the world (of Warcraft) to get him and only 717 did. Addons like Weakauras make certain mechanics trivial these days. One interesting note is that this is one of the shortest end-raid encounters. It's a fast and furious encounter which wipe counts can add up significantly.
TLDR: A lot of people tried to kill this boss, very few did, and you had a very short window to get the kill.
The Case Against:
It’s difficult to truly understand how difficult this boss was against KJ and Arthas because it was a mid-expansion boss. The very short window the boss was open does make it more difficult, but it also makes it more difficult to compare it to the previous examples. However, Method was able to take down Blackhand within 10 days of Mythic raiding opening it. While they may have had more resources and the overall player skillcap has been raised, it’s over a month faster than KJ or LK.
Mythic Kil'Jaedan (Tomb of Sargeras)
Active subscriptions while this encounter was active: Unknown (Most likely anywhere between 7-10 Million)
Number of guilds that were killing bosses during this tier/raid: 27,114 (Heroic guilds), 8,894 (Number of guilds that killed a Mythic boss in ToS)
Number of guilds defeating the encounter while active: 851
Release Date: June 28, 2017
First Kill: July 16, 2017 (18 days after release)
Last Date for “counted” kill – November 28, 2017 (Release of Tier 21 Antorus)
Availability for active kill: 153 Days
The Case For:
Including Mythic KJ in this analysis may be somewhat controversial. Like other raid bosses mentioned previously such as C'Thun, this encounter was plagued with tuning adjustments made as the top guilds were progressing on the encounter. In fact, the entire instance of Tomb of Sargeras was criticized for its tuning. According to WoWprogrss statistics, 1.91% of all active guilds killed Mythic KJ while it was available. That's slightly above 25-Man Heroic LK (1.85%). Furthermore, KJ's mechanics were also praised by top-end raiders as being one of the most difficult encounters to master. Much like Mythic Blackhand, KJ was also a guild killer. Many top-raiding guilds threw in the towel as did other guilds. It also had a very low overall percentage of guilds killing it, at 1.91%. This analysis deems that KJ deserves to be considered one of the hardest encounters in WoW history.
The Case Against:
Just looking at the overall numbers, it appeas as though Mythic Blackhand was clearly a more difficult encounter for guilds than Mythic KJ. The overall guild raiding population was higher during Tier 17, but the subscriber numbers are unclear for Tomb of Sargeras. KJ was available for 20 days longer than Blackhand with an arguable higher amount of raiders raiding Mythic content. To be exact, 8,894 guilds killed a mythic boss in Tomb of Sargeras, while 7,997 killed a mythic boss in Blackrock Foundry (16,132 killed Mythic Kargath, and 5,057 killed Mythic Imperator in Highmaul, the previous raid to BrF). Furthermore, a smaller percentage of guilds (0.8%) were able to defeat Blackhand as opposed to KJ which had a 1.91% kill-rate amongst guilds. The resources available for guilds for these two encouters are virtually identical.
While top-end raiders may have praised the encounter's difficulty, it did not stop Method from killing him in less than 3 weeks. However, the overall raiding population paled in comparison to ICC.
This was not an easy analysis by any means. With this information, you could make the case that any of these three bosses would be most difficult. However as an analyst by trade, I must come up with a recommendation/conclusion. With all data and factors under consideration, I will make the argument that the most difficult encounter to defeat was:
The Lich King (25-Man Heroic)
One of the most glaring statistics I analyzed was the number of guilds progressing through each instance in order to get to one of these bosses, and the number of guilds that actually killed the boss. It's easy to look at the overall raiding figures and say “Well, just because a guild killed a mythic boss doesn't mean that they were trying to kill the last boss in the instance.” I agree. We are now going to use the data to see how many guilds were progressing throughout these instances and how many guilds had the opportunity to kill the abovementioned bosses.
16,103 guilds killed 25-Man Heroic Lord Marrowgar, while the 25-Man Heroic raiding population progression counts remained steady of about 10,000+ guilds until Heroic Sindragosa. That means around 11,000 guilds were actively progressing 25-Man Heroic ICC, while only 1,101 defeating Arthas. The most glaring number is 5,673 guilds killed 25-Man Heroic Sindragosa. That means 4,572 guilds were knocking on Arthas' door, only to get knocked out. Only 19% of guilds with the opportunity to kill Arthas were able to defeat him.
For all of you 10 Man Heroic fans out there, the numbers for 10 Man Heroic Lich King are as follows:
5,664 guild kills for a 6.71% guild-kill rate.
21,323 guild kills for Sindragose, which means 26.5% of guilds that killed Singragosa on 10-Man Heroic killed 10-Man Heroic Lich King. The 25-Man encounter was harder...
A quick side note: Wowprogress lists overall numbers of killing Mythic Blackhand and Mythic KJ to be higher than what will be listed below. Some of these kills were achieved after the next tier of raiding was released. As mentioned at the beginning of this article, only “active” kills are being analyzed. “Active” kills are kills that were achieved before pre-patch/release of the next tier of content.
Let's take a look at the other tiers for insight. Unfortunately we do not have comparative data for Tier 6 Sunwell for Kil'Jaeden. The only Sunwell data we have is how many guilds cleared the entire instance.
Taking a look at Tier 17 data, it is clear that guilds were better at killing Blackhand once they were able to conquer The Blast Furnace as opposed to getting Arthas after beating Sindragosa. 1,206 guilds killed The Blast Furnace (the second least killed boss in BrF and widely agreed to be the 2nd hardest boss in the instance), while 717 guilds cleared Mythic Blackhand. That means 59.4% of guilds were able to kill Blackhand after clearing the Blast Furnace.
The numbers for Tier 20 Tomb of Sargeras are also compelling. 1,383 guilds killed Fallen Avatar while 852 guilds were able to get KJ. That means 61.6% of guilds were able to get KJ.
So judging 3 out of the 4 fights listed above solely on the percentage of capable guilds were able to beat the boss. The TLDR is as follows:
25-Man Heroic Lich King – 4,572 guilds had the best opportunity to kill him. Only 19% (1,101) of guilds could get him.
Mythic Blackhand – 1,206 guilds had the best opportunity to kill him. 59.4% of guilds could get him.
Mythic Kil'Jaedan – 1,383 guilds had the best opportunity to kill him. 61.6% of guilds got him.
This data clearly shows that more guilds had the best opportunity to kill Heroic Lich King than Mythic Blackhand or Mythic KJ. And, a lesser percentage of guilds were able to kill Heroic Lich King. Let's not forget, Heroic Lich King had a 30% overall nerf while active.
There were plenty of players trying to kill LK, but very few did. Proportionally and statistically the least killed encounter when compared to its counterparts, sub numbers, and overall raiding population.
However, the one key piece of data missing is the number of guilds actively raiding Sunwell Plateau while it was active. If we could compare those numbers, it could change my conclusion. Kil’Jaedan is colloquially known as one of the most difficult bosses to defeat, many players never even stepped into Sunwell to begin with. That data isn’t available to me; therefore I cannot come to an ironclad conclusion. But if I were making a recommendation based on the data at hand, 25-Man Heroic LK is most difficult encounter in the history of the World....of Warcraft. Terenas Menethil said, “No King rules forver.” Maybe time will tell if another boss can be as difficult at Arthas...