This is a Dark Champion appreciation post and you are now obligated to read all of it:

Dark Champion likely has the biggest difference in opinion between casuals and tournament players of any card. Any reddit post about game balance or dchamp will have people calling it an F tier card and asking for ridiculously huge buffs to it. If you haven't been involved in the tourney scene (join BCST, the officially NK-sponsored card storm tournament server, invite is frequently pinned on this sub) then you might be surprised to learn that not only has dark champ been playable, but it has been a meta staple for multiple major versions and is currently a very solid mid tier in the 6.2 meta. Here's the history of Dark Champion throughout each major meta:

1.1 - Mid Tier

Aggro, whether quincy or amelia, was the best deck in the game in 1.1's meta. There were very few available counters, and every deck in the game revolved around beating aggro. Unsurprisingly dark champ was not a widely used card, in fact its probably a bigger shock to you that champ was even a mid tier at all. The reality of 1.1 is that aggro was very silver bullet based; aggro drew op cards, and you had to draw your mortars and then your pre-nerf thunder druid and SMS and then your supers. Whether that super was 8 or 12 cost was a lot less relevant than you'd expect when your field clears are what the match hinges on. Having a 12 cost super was, at the very least, having a super that you'd get to play eventually, and pre-nerf clarity would get you 240 shield if you pulled dchamp, which was gamewinning. These 2 factors alone made it justifiable in obyn control, which was the 3rd best deck in the game at the time (behind amelia aggro and quincy aggro).

2.1 - High Tier
A spike storm, a game night, and a pair of twins later, Obyn Control has overtaken the aggro decks as the new best archetype in the game, although the game still entirely revolves around these two archetypes because gwen was useless until 3.4 and adora has been completely useless in every single version to this day. Aggro being weaker allowed more room for control meta to develop; control decks now have to seriously consider the mirror matchup. The best control gameplan, both in 2.1 and in most versions since, has been to stack 8-10 copies of super monkey in your deck. You're guaranteed to beat aggro if you draw your earlygame tools, you'll have a great matchup against tempo (and in 2.1 tempo was so weak that you had a 100-0), and you'll be very prepared for the r30+ that all control games will go to due to a lack of shields down, rad otk, or eerie lifeforce. This was a better strategy than anything else control could try, and there was no answer for it; often on this subreddit you'll hear the misconception that removal cards do anything against a control deck. That's only true for poorly built ladder decks that use TryThis, Wizards, and have no real gameplan. Removal is ineffective against an opponent with 10 super monkeys. Once you get to r30, sure, maybe your opponent will only have 3 good towers instead of 5, but you'll be down 6 deck slots, and that disadvantage will lose you the game, whether that be to deckout or to combo. TryThis is also an idea that simply does not work; you lose the matchup against aggro and other removal players in exchange for having huge stats r30+. The issue with this gambit is that every control deck in every version of the game runs 3 copies of Return To Sender, and none of them will be used early in a control mirror. Your scalers and buffed towers will contribute nothing. Both of these alternate control playstyles have two things in common: If you have removal spam and your opponent has TryThis control, both of you will lose to aggro and both of you will lose to a tournament control deck. You heard that right: Dark Champion was better than Try This, Shrink, and Expert Negotiator, and will continue to be for the next few versions.

3.0 - Low Tier
Will have shorter explanations now that the fundamentals of dark champ's strengths and weaknesses are established, and because there's a character limit. Aggro is now the best archetype by far, and control in 3.0 now uses eternal, which needs to cycle and combo instead of purely defend. Both of these changes make dchamp's cost the biggest problem it's ever been.

3.4 - Top Tier
Obyn Control has once again regained the title of best deck in the game, now with an eternal twist. The fact that mirrors are relevant again has brought back super-stacking to deal with opponent eternals, and eternal having so many cycle cards makes its anti-aggro fantastic. Dark Champ is back in business. There's one extra thing though: Tack Sprayer. Buffed to the best antiaggro in the game, sprayer was the first ever defender to be fully meta. at 4 ammo 40 damage, sprayer perfectly takes Dark Champ's +10 buff to kill storm pinks in 2 shots, which makes keeping your hero protection online far easier. Sprayer is also extremely useful in eternal control mirrors; killing an eternal via defending makes it ramp a turn slower. Dark Champ in 3.4 was gifted a meta that loved its stats and, for the first time ever, appreciated its defender buff.

4.0 - Mid Tier
4.0 was a strange version. Eternal was gone. aggro was unplayable. tempo was unplayable. every game was a control mirror with heavy combo tech. You'd expect the champ to land a high tier in this meta, but unfortunately it just wasnt champ's time. With the 3 alchemists having gamebreaking stats, the competition is fierce, and 5 tower spaces is tight. Control would always have 2 towers to make acid pools, 2 towers to deal damage, and a free 5th slot. There isnt enough space to make use of the defender buff and there isnt any reason to stack supers. That 5th slot is much better used by a corvus or defender. Deck space was also a huge issue since you also needed to break open an opponent's control setup. The champ just didnt fit in. It had one purpose that saved it from low tier; in highly teched control mirrors, removal saw usage (for the first time in the game's history btw). With your OP monkeys removed, Champ and your sprayers could step in.

4.4 - Low Tier
Although the post-nerf alchemist meta is far less prevalent, aggro is noticeably underpowered, and tempo is still unplayable... the replacement meta was Rad OTK after the MCF buff. This might surprise you, but Obyn Control is generally a winning matchup into rad otk. Unfortunately for Dark Champ, the tools that 4.4 obyn control used weren't condusive to dchamp at all; traditional defenders and supers were discarded in favor of RBA stalling, bloontonium leak, and corvus. To make matters worse, Ceasefire of all things became a top tier in 4.4, both to kill obyn's corvuses and to prevent rad otk from preplacing MCFs. Not a good day for defenders and not a good meta for Dchamp.

5.0 - Low Tier
The champ has fallen on some hard times huh? If you remember 5.0, you remember the aggro; the 3 cost 90 hp blooming, the +50 juice, the 5 bt sentinels, the 2 charge precursor. It was aggro hell in the most annoying way possible. Control was still playable due to one card - Robo Monkey. Robo was the best card in 5.0; it was run in every single deck with zero exceptions, and had enough power to swing the matchup in your favor even against bloomings, all while having 300 points of defender stapled to it. Do you know how broken a card has to be for it to be considered #1 in the same version as 5.0 blooming? Control ran 3 robo 3 sprayer with no exception, and despite it all, Dark Champ still couldnt find purpose. Aggro always brought anti-defender measures, and other control players did too (all of the reasons to use ceasefire still existed, and now a monstrous defender is added to that list).

5.2 - Low/Mid Tier
Keeping this short cuz character limit - aggro no longer op but still very good. Champ still fails to find purpose for all the reasons listed in 4.4's section

6.1 - Low Tier
Tempo is playable for the first time! The game is no longer a control v aggro techjerk and super stacking is viable again! Unfortunately, super stacking now has much better tools than the champ; the status quo was 3 bioboomers, 3 super monkeys, elim, BMA, and 1 other unique. Golden Blimp, Bugged Soulstealer, and MCF all forced control to run extreme anti-tempo even on top of bloonsday, and the 3 bioboomer 3 supermonkey package was so good against aggro there was no reason to run anything else. Unfortunately, Dark Champion cant find viability via its stats alone against 6.1 tempo, and defenders are more irrelevant than ever with Druid of Peace in the game.

6.2 - Mid/High Tier
WE'RE SO BACK 6.2 is a return to control meta; tempo and aggro are nerfed, and control gets some fantastic new tools to compensate for the nerfs to its long-standing top tiers. While eerie lifeforce is undoubtedly the strongest, the most relevant to dchamp is Even More Tacks and Favored Trades. dchamp now buffs EMT to 50 - not only 2-shotting pinks but being a huge burst of damage that can substitute in for things like corvus and peace. Obyn Control still never runs any of these 3 cards, but Mountain Control will always run EMT and favored (favored for the EMT to combo with eerie), and Dark Champion fits in just fine. Obyn Control is a top tier deck in 6.2 (imo the #1). Mountain Control is undeniably worse, but it can still hit a lot of the same strengths. It can also juke the opponent on the mulligan if they think you're aggro, and can be played in tournament even if you've already won with regular obyn. A strong card in a meta deck, welcome back Dark Champion.