One of the interesting dynamics of the game as a whole is the Nemesis system, so I'm curious as to how each of the heroes stacks up against their nemesis. Wwhich heroes are uniquely suited to take on their nemesis from a gameplay perspective, which ones are not particularly effective but thematically linked, which manage to do both? So, without further ado, here's my own thoughts, at least for the heroes and villains I have access to (Core set, Rook City, Infernal Relics, Unity, and Ambuscade.)
Skipping AZ, Bunker and Visionary for the moment, as I don't have their Nemesis decks.
Fanatic: Definitely more on the thematic side against Apostate, their decks are basically mirrors of one another, though hers focuses on self-sacrifice, his on accumulating power. Certain of her cards, in combination, can be very effective against some of his tactics, though -- Chastise can keep things like the Relic Spirit alive when huge global attacks come out, and Divine Sacrifice + Undaunted can mean that Gauntlet of Perdition doesn't harm anyone. Final Dive is a godsend (Ha-HAH) for when the Orb of Delirium and the Tome of the Unknowable are both out. Further, given Apostate's relative lack of personal DR, Fanatic effectively starts with a 4-damage base power against him.
Haka: Ambuscade does a lot of damage, and Haka can heal a lot of damage. Rampage is perfect for taking out a stream of Devices, and Haka's selective-damage powers, like Taiaha, can keep him from accidentally triggering things like the Sonic Mine. Meanwhile, Ground Pound can put Ambuscade at a standstill when he manages to get a lot of devices out. And adding the +1 to Haka's already formidable attacks helps him take the hunter down that much faster.
Legacy: Let's face it, Legacy's whole deck is hugely useful against just about any villain, and this is the case with Baron Blade -- Heroic Interception keeps his devastating cards like Devious Disruption from being a total party wipe, and Take Down keeps him from putting more into his trash. Interestingly, this works out badly for Legacy, since he opens himself up to more damage with those plays -- but his other ongoings, like Next Mutation, Fortitude, and Superhuman Durability actually make that work to his advantage against Blade -- boosting an attack that might have hit for 4 up to 5, with those cards out, bounces it back down to 1 damage. But, again, this all applies to most villains, so Legacy, while effective against Blade, isn't especially great against him compared to other villains.
Ra: Ra likes to burn stuff, and the Ennead are great at giving him lots of targets. The Ennead are also great at belting out fire damage, meaning Ra can significantly weaken their offense with one card play. And even though they have no ongoings, the +1 from the Nemesis boost makes Drawn to the Flame a good round-one play, with all Ra's buffs turning it into a game-winner. Flame Barrier is also a no-brainer play, since Ra's going to be taking a lot of damage and the +1 makes the Ennead feel it.
Tachyon: Thematically, yeah, this doesn't make a whole ton of sense, but Tachyon is absolutely the best person to take on the Matriarch for one reason: Hypersonic Assault. Hit Matriarch first and you wipe her board clean with no fuss, particularly useful after she plays Darken the Skies. There is one interesting mirror parallel gameplay-wise: Like Tachyon, Matriarch really likes playing all her cards very, very quickly, and has an eye-piece that lets her play extras.
Tempest: The king of global damage is, of course, matched up against someone who likes to put a crapload of minions out. A boosted Grievous Hailstorm can wipe a board -- and the Elemental Subwave Inducer can help you pick and choose which minions to leave alive at the end of it (keeping the Soldiers out instead of the Frosthounds, for instance). Into the Stratosphere is also handy for delaying a card for a round, such as Forced Deployment.
Wraith: Maia is, perhaps, the most directly and best suited to taking on her nemesis, thanks to her ability to play two powers, scan the deck, and keep him from doing damage consistently. While there's still risk, since Spite plays two cards a turn, with a little luck Wraith can shove his drugs and Lab Raids to the bottom of the deck, picking which order they come out. Failing that, her Nemesis bonus lets her force a Throat Jab through anything short of an H5 game, and failing that, Stun Bolt doesn't need to do damage to apply the debuff, so having two of them out effectively neuters him and lets the heroes get way ahead of his healing.
Expatriette: Against Dawn, Expatriette has a few things going for her -- RPG Launcher is fantastic, given the number of ongoings Dawn has, and Pride and Prejudice becomes at least 6 damage against her. One unique thing about Dawn is that you don't necessarily want to clear her minions out, but with how many of them do damage, keeping them alive is rough -- but a Submachinegun with Liquid Nitrogen Rounds can keep it from being too painful and Reload and Speed Loading can keep her bringing them out. Alternately, Assault Rifle lets you pick and choose which Citizens you put down, always handy with a trash-revolving villain like Dawn.
Mr. Fixer: His nack for Irreducible damage is really handy when you have to manage which Thugs and Underbosses to target -- leave the Deputy and his Corrupt Cops out to focus on the others while Fixer and his Dual Crowbars clobber whoever needs it directly. That tool in particular is handy for the Chairman and Operative, since it's always fun to let the Nemesis Bonus stack up. Grease Gun is also a godsend once the gunmen come out, and keeps the Operative and Chairman from retaliating.
Argent Adept: Like Legacy, there's not a ton about AA that makes him specifically good against Akash'Bhuta, but he is one of the few with power-based Ongoing and Environmental destruction, which can be handy, given how Akash interacts with the environment. His best asset is probably being able to give other players turns -- an extra helping of Powered Shockwave or Scorched Earth can do serious damage to all the targets she puts out. Also fun is when you realize that Akash'Bhuta has only one card that lets her do damage to the heroes (Entomb, an ongoing which, as mentioned, can be easily taken care of) -- the only other times she does damage is to herself, when her limbs go down. Argent Adept can get a lot of mileage out of boosting her with Syncopated Onslaught right before taking out her limbs with little risk.
Nightmist: Another generally useful character -- most of what she can do to Gloomweaver works on other villains. Her Nemesis bonus, however, is a handy buff for spells like Heedless Lash or Oblivion, in which it's effectively a +2 or +3 once she has her Amulet out. Astral Premonition and Mistbound are also great for putting painful cards like the Cursed Acolyte and the relics where you want them.
Freedom Six:
While I don't have Shattered Timelines yet, I did notice one thing about the Freedom Six variants and how they go against Iron Legacy. Tachyon gets everyone to draw cards; Bunker gets Ongoing destruction; Wraith gets a damaging power; Absolute Zero gets a direct damaging power; Unity can get her bots out without equipment; Tempest gets extra card draw.
Wraith, AZ and Unity's powers are all about speeding up their play and doing damage first turn -- very important in a hard-hitting game like Iron Legacy, who does so much damage the heroes might well not get three or four turns to set up. Bunker gets an ability to take out Ongoings right off the bat -- and of the six, he's the only one who has no ability to do so normally. Tachyon and Tempest get card draw, helping the whole team get the stuff they need that much faster.
In short, they're all built for a fast paced, desperate game, which is exactly what Iron Legacy usually delivers.
Feel free to add your own thoughts.