This is not a walkthrough, but a set of tips to improve your chances to beat Across the Obelisk on Madness 16.
The best way to survive in Across the Obelisk is through Vitality and Regeneration auras. Block, Shield and Healing are cool, but they are just sub-optimal in the highest difficulty setting.
For Vitality, the trick is that health bonus does not go away at the end of battle, or when you lose the charges. In other words, each vitality charge actually heals you by 5 health. Since vitality affects max health, it also work as 5 block.
The trick for Regeneration, on the other hand, is to have both middle characters with the perk to heal their sides. In practice, that will double the effect of regeneration, making each character be healed by their aura and the aura of the hero by their side.
The best cards for survival are presented below:
Vitalizing Serenade gives both Vitality and Regeneration to all heroes, being an extremely powerful defensive card. The only problem is the requirement for Stanza I, which is why Gustav is one of the best supports in the game.
Battle Shout is one of the best cards in the game. First, it dispels Slow, which allows you to act before opponents and avoid some of their attacks. Second, it gives Vitality and Reinforce, which directly contribute to your survival. Finally, it increases damage, allowing you to defeat opponents faster and receive less attacks. That’s why Warriors are also among the best supports.
Stockade is a straight forward survival card, granting vitality to all allies, as well as some block.
Healing Rain has no cost, gets you Wet and grants Regeneration to everyone. Regeneration on opponents will not be a big deal, since you should be doing way more damage then them. Wet on allies is a good thing, because you can make it into Bless using Baptism (Healer card).
Premium Meat is the best supportive card in the game, which makes Yogger the best support. In short, it is a free card that gives you Vitality, Regeneration, Sharp, Bless, Powerful, Stealth, Fury, and any other buffs. The same is valid for Gourmet Meat.
To reach maximum damage output, you need to stack auras into a single character and curse your opponents. The main damage auras are Bless, Sharp, Powerful, Fury and Stealth. The main curses are Vulnerable and Mark, as well as some character specific bonuses (like Sight for Sylvie).
Bless is the reason why you should have a Healer in your party, despite the actual best healers being Yogger and Gustav. There are multiple ways to apply Bless, but the most effective way is to transform Wet into Bless using Baptism. You can get Wet from Healing Rain, and there are some specialized strategies to stack Wet (like using Poison Flask with Dillute). Another less optimal option is to use another Scout with Stanza generating cards and Ballad of Conquest. Once you apply your first stacks, Premium Meat will help reaching the cap.
Powerful is a straight forward buff that you can easily reach the cap with Battle Shout, Ode of War (for Gustav), and equipment. Since +100% damage is better than +60%, you should get the perk to increase damage by 10% per charge and lose all charges by the end of turn.
Sharp is one of the reasons why Grukli and Sylvie are better damage dealers than Reginald and other options. Since you should have Gustav and Yogger in the party, it should be pretty easy to reach max cap of this aura using cards like Grinding Wheel, Sharpen, and Chant of Accuracy.
Fury is one of the reasons why Grukli is the strongest damage dealer at the moment. You simply cannot beat +500% of damage, which can easily be reached with Infuriate. Premium Meat will contribute to reach max cap, and heal the bleeding side effect as a nice bonus.
Vulnerable is one of the most important curses to increase damage, and you should make sure your team has the perks to increase physical damage, and increase max charges. You can easily reach max cap Vulnerable with cards like Piercing Howl, Intimidate, Uproot, and Hunter’s Mark.
Mark is another straight forward curse that increases damage, and it is even more effective when using Grukli as damage dealer, because of the perk to decrease slashing resistance. Conveniently, the main cards to increase Mark are also used to inflict Vulnerability, like Hunter’s Mark and Intimidate.
Yogger is the best Warrior in the game for support, because of Premium Meat. Just level him up with all traits on the right side, and you will understand why other warriors are no match for him. Vitality is better than healing and block to keep the party alive, and you cannot beat +25% to all auras.
Gustav is the best Scout for support, because Vitalizing Serenade requires Stanza. Get all level up traits on the right side (Level 5 is optional), and he will become an aura machine with Chant of Accuracy, Ode of War, Ballad of Contest, and Vitalizing Serenade.
You need a healer to provide Bless efficiently, and Nezglekt is the character of choice because of his unique traits. Night Terror is really strong against bosses, and Fated Future will allow Grukli to use even more attack cards in his turn. Resourceful trait is recommended over Mind Devourer to allow you to use Banish and Expected Prophecy for free, increasing your odds to get the cards you want every turn.
Grukli is the best damage dealer because he can accumulate more auras. You just cannot beat +500% damage from Fury, and the side effect of it is completely countered by Vitality. For level ups, ignore Bleed completely and go for Onslaught, Offense Mastery, Dual Wield and Endless Fury. Focus on slashing attacks with repeat, especially cost efficient cards like Carnage.
The goal of any deck is to consistently deliver the expected cards for the tactic. In other words, you want to draw specific cards as often as possible. For that, it is recommended to always keep the deck with the minimum size. To avoid running out of cards, you should also aim to have at least five cards without Vanish.
Cards with no cost and the ability to draw at least one card are always good in any situation, because they effectively reduce the size or your deck by one while providing some extra effect. It is the case of cards like Deflect, Enrage and Setup, for example.
Avoid adding any cards that do not contribute directly to your tactic, and even if they do contribute somehow, think about the cost of opportunity. You should always ask yourself if the card you are adding will be more effective than the card you will need to remove to keep the deck size at minimum.
control the Your goal is to have your damage dealer act after all other characters, so they can give stack auras on him, but before all opponents. Ideally, Yogger will be the fastest in your team, so you can slow opponents with Piercing Howl. The second fastest should be Gustav, allowing you to use Trace on Nezglekt and set up a good first turn.