Here’s a simple deck of heroes that can help you progress through the Chaos Trials.  Each individual build will have more detail.  There’s some general tips in the sections below as well.

If you spot any typos/errors, have any suggestions, etc., please let me know in the comments and I’ll reply as soon as possible.

< Progression Overview >

Here’s a brief explanation of how these heroes will be used throughout trials:

• C1: Vanguards have shields that reduce damage from projectiles.  Flame Auras are not a projectile defense, so they will be used to ignore the Vanguard mechanics.
• C2: Cyborks disable traps, nodes, and auras.  Cannons, PDTs, and Flamethrowers are the next best alternatives.
• C3: Geodes create bubbles that reflect projectiles.  Flame Auras can ignore this as they are not a projectile defense.
• C4: Berserkers (aka Lady Orcs) resist slow, move very quickly, and can deal a lot of damage to blockades.  They are susceptible to CC effects, so you can use Cannons with Stun Fire shards to disrupt them and/or you can micromanage them with hero damage or concentrated damage (Flame Aura/Weapon Manufacturers/Proton Beams).
• C5: Assassins periodically latch onto and silence your active hero.  Also, Cyborks are back.  You either need to kill assassins quickly with your defenses and/or control them with CC effects.  Otherwise, you won’t be able to repair blockades and assist lanes.  This is generally built similarly to C2 with Stun Fire on Cannons and Flamethrowers should have more range now if you’ve farmed your Deadly Strikes from C3.
• C6: Hex Throwers can attack your blockades at long range, creating a field that lowers the defense power of nearby defenses.  EV2’s Reflect Beam is a hard counter to them.  If you choose not to get EV2, you would need to create kill zones with stacked Flame Auras in places where you see them stand or cleverly use line of sight to force them to walk through several Flame Auras.  Geodes are back, but they’re not much of a threat if you’re using Flame Auras.
• C7: EMP Kobolts can quickly bomb your sub cores or your towers (and disable them).  Again, Flame Auras are strong here, especially because they can hit ground and air.
• Hero EV2: She clears lanes and takes out most bosses quickly.  She can kill Siege Rollers, but it requires some slightly tricky maneuvering.
• Hero Monk: He can handle Siege Rollers quickly.  You can also have him handle the regular stuff if you want, but EV2 is generally more effective.

< Why get EV2 as your first hero? >

Technically, you don’t really need extra heroes to clear the Chaos Trials, but I feel EV2 offers the most convenience on your journey to C7.  Other heroes have their uses, but I feel they each offer less features than EV2 if you want an easier time getting through the Trials.

• Most heroes need to put points into Range Gambits to get more out of their defenses, but EV2’s best defenses don’t use Range Gambits.  This allows her to crit chance hybrid early on at lower ascension levels by putting points into both crit chance categories (hero and defense).
• At C6, you will encounter an annoying minion that can heavily deal damage to targets at really long range with spear throws.  EV2’s reflect beam defense can reflect those spears, so you can use Reflect Beams to preserve your blockades.  Without Reflect Beams, you would need to either quickly use a hero to deal with the minions, create a kill zone where they would gather up, or cleverly use line of sight to force them to take more damage as they walk to your blockade.  As long as you have a relic with a defense health stat close to your relic progression tier, you don’t need much else to make your Reflect Beam work well.
• EV2’s Proton Beams deal high damage and are a great utility defense.  They are the most precise way to create slow zones for ground minions (including bosses).  Once you have a Power Transfer shard on a Medallion, they can be upgraded to deal high DPS to enemies that walk through them.  Once you acquire the Frosty Beams shard, the Proton Beams now have a chance to freeze targets, which further impedes enemy movement through that lane.  Outside of C2 and C5 (nodes can get disabled), Proton Beams have a strong combination of powerful effects to keep your lanes under control.
• EV2’s Weapon Manufacturers are great when you get to farming or want to shut a lane down.  Even though you can’t upgrade it, it has the power of some upgraded defenses.  If you’re farming, this means you spend less time upgrading as you repeat your maps.  Once you get some good damage on your WMs, you can stack the nodes together or combo it with other defenses to create potent kill zones that pretty much delete minions.
• EV2’s Ability Power Proton Charge build (listed below) can quickly take out minions and most bosses (except Siege Roller).  Taking out a Siege Roller requires timing with the Anti-Gravity bots, but it’s a slower process compared to some other heroes.  This covers most of your needs from a combat hero.  If you want a more efficient way to clear Siege Rollers, consider the hero monk build listed below or any projectile-based damage hero that can kill a Siege Roller.

I feel most other heroes have very specific caveats to make them strong or have less options to make trials more convenient.  In the end, you may want to collect them all for Mastery or a different play style experience, anyways.  These are just reasons why I think EV2 is particularly effective for progressing through the Chaos Trials.

< Generally Useful Shards >

The “best” shards to be using  really depends on its role and your current Chaos tier, so it’s not always an easy question to answer.  The main two variables that can influence your defense shard choice are your defense crit chance and your defense speed.  Defense crit chance can reach 30% by the time you reach ascension 60 (20 points in defense crit chance ascension), and defense speed approaches the cap as you get closer to C7 relics.  Many shards will depend on how you want to build your hero or defense, but there’s a bunch of general shards that are effective.

Here’s a breakdown of general shards you may want to stock:

= Campaign =

Fortification (+%HP): This is a staple shard for any blockade.  You can collect extras if you want to use any other blockades or just want your defenses to have more HP early on, since you don’t really have much shards to use.

Defensive Critical Damage (+%def crit damage): This is a staple damage shard.  Primarily you will be using this for marks, but it can be extra defense crit damage on medallions.  Early on, these have minimal impact until you reach 30% crit chance.  If you can’t achieve a critical hit, then critical damage doesn’t do anything.

Construction (faster repair/upgrade in combat): This can help you deal with heavy lane pressure when your blockades are in danger.  It’s not a requirement, but it’s often a great choice for gloves if you need it.

Worm Scarf (-%incoming damage): For many heroes, this is a first choice for helms, since there’s usually nothing better.

Speed Boost (+movement speed): There’s very little useful boot shards in the game, and moving faster is just highly beneficial for responding to combat situations.

= C1 =

Bulwark (+%armor): For most heroes, this is an easy choice for a chest piece shard, since you generally want to keep your hero alive and there’s usually no better options.

Critical Strike (+hero crit chance%): This is generally a first choice glove shard for heroes that want to optimize damage.  Compared to defenses, heroes can achieve a 40% crit chance with this shard and are not capped at 33%.

Destruction (+%defense power): Early on, this is going to be your only choice for increasing the damage of your defenses.  For best results, use this on Medallions.  Once you get higher crit chance, you can use Marks with Defensive Critical Damage or Medallions with Power Transfer.  Other shard slots are often taken up by other useful shards.  Once you don’t need destruction, don’t toss them out in case you might need them for Mastery.

= C2 =

Defensive Critical Strike (+defense crit chance%): As far as trials are concerned, this is a temporarily useful shard that can let you have a high crit chance (25%) until you max out your defense crit chance ascension.  Defense crit chance is capped at 33%, and the ascension puts you at 30%, so the extra 3% isn’t worth the shard slot by then.  You may need these later for Mastery, so keep them after you don’t need them for trials.  Mastery limits your ascension, and these will be the main source of achieving defense crit chance for optimal defense DPS.

= C3 =

Deadly Strikes (+%defense range): For many defenses, this is essentially a DPS increase because targets will be in range of defenses more often.  This is often a first choice for damaging defenses.

Shielding Guard (%chance to give shield to equipped defense based on % of HP): Since there aren’t too many options for blockades at this point, these can soften damage until you get something better later on.  Later on, the damage reduction is often not enough to warrant a slot when you can use more powerful effects for other things.

= C4 =

Defense Rate (+%defense speed): These provide a significant DPS increase early on.  Once you approach the defense speed caps (closer to C7 relics), this increase becomes negligible.  You might need these for some defenses in Mastery, so keep as needed.  Stats are capped there, so you will be under the speed cap in some tiers.

Power Transfer (+defense crit damage based on % of defense power): Once you achieve a high defense crit chance, these provide significant DPS increases.  They’re mainly used with medallions, but they can be another source of defense crit damage increase after Defensive Critical Damage on marks.

= C6 =

Sharpened Spikes (%chance for blockade to stun on attack): This is often one of the best choices for blockades that attack.  Stunning a minion on your blockade is another form of damage reduction.  Consider pairing this with Explosive Guard if you want to use a blockade that doesn’t attack frequently or want another way to apply the stun.

—

If you’re unsure if you’ll be using shards not listed above, here’s some general guidelines:

• if it’s a hero specific shard, you generally don’t need more than one
• keep at least one of each shard just to have a copy ready if you need it for a build
• for cooldown-related hero builds, consider stocking some Inspiring Strikes and Inspiration
• for ability resource management needs, consider stocking shards like Channel, Power of Storms, and Mana Capacitor
• Vampiric Empowerment stacks with Power Transfer and is another source of Defense Power increase (can also be used to increase the damage of some totem-related blockades)
• Power Gambit is great for Hero Damage builds
• the Retribution type shards are often the best filler shards if you have no better options on the associated armor pieces

< Relics Overview >

There are 3 relic types in this game (orbs have been discontinued):

Totem

• These have a primary stat of defense health and are typically used for blockades.
• Fortification is generally the first shard to use on these, since the extra health increase works well here.
• The Vampiric Empowerment shard works well with Totems, since it can convert a lot of defense health.  You might use this to increase blockade damage (usually Abyss Lord blockades).

Medallion

• These have a primary stat of defense power and are your only option for damaging until you have a higher defense crit chance.
• To maximize damage with shards, use Power Transfer, followed by Defensive Critical Damage and/or Vampiric Empowerment.
• With Power Transfer on a medallion, Proton Beams and most 20 DU defenses scale DPS really well with upgrades.
• Sky Guard Towers have poor crit scaling, so they are generally better with Medallions.
• Consider using Medallions more when you want to deal more consistent damage (usually for standard AoE minion clear) or want better benefits from upgrade scaling.

Mark

• These have a primary stat of defense critical damage.  These are not effective until you have a higher defense crit chance.  If you don’t crit, defense crit damage does nothing.
• To maximize damage with shards, use Defensive Critical Damage, followed by Power Transfer, then Vampiric Empowerment (if you don’t need the 3rd slot).
• Consider using Marks more when you don’t need upgrade scaling on your defenses as much or when the role of your defense is to achieve high burst in a short period of time.

NOTE: There is often a debate between medallions and mark.  In the end, with optimal setups, both are capable of dealing enough DPS for the Chaos Trials.  The only time you would want to choose one over the other are for the reasons listed above.