It's dangerous to go alone, take this! This guide has nearly all my relevant knowledge about Emberquake, engineers and game mechanics.

Emberquakers are tanky damage dealing builds and are the most well-known cookie-cutters of all. Emberquake alone does enough damage that the player can concentrate on defensive skills with the remaining skillpoints.

• Easy-to-use
  
• Semi-ranged
  
• Powerful
  
• No gear-dependency
  
• Conveys weapon effects

• Only avaible late-game
  
• Complicated damage formula

The list of pros is quite convincing, isn't it? After all, that's a cookie-cutter character. At first I didn't like it as much as I liked my cannoneer. Of course I didn't like it, it was like building a Frozen Orb Sorceress in Diablo II, no real attack skills until you finish the first playthrough.
When I managed to unlock Emberquake, everything changed. Now I really like it, it's a powerful tool of having fun!
On the other hand, Flame Hammer does the same, except that Flame Hammer's splinters can't convey weapon effects like Emberquake fissures can. If you're not going to do any spell-trigger or DoT stacking build, Flame Hammer works just as good for you.

Yes...
• ...if you have long-term interest in the game.
  
• ...if you like defensive characters.
  
• ...if you like supporting your friends and killing things fast at the same time
No...
• ...if you just want to rush the game for a walkthrough, try Flame Hammer instead!
  
• ...if you have a dislike for defensive approaches.

Main skills are considered to be mandatory for the build. Of course, it's your character, if you don't like any of the skills, you can leave it out of your own implementation, but it is not recommended, as these skills are required for the effective usage of the build.

• Emberquake 15/15
  Main attack skill of the build. Virtually, it is a multiattack skill with moderate damage and an immense attack speed, Emberquake strikes 8 times a second, each strike can hit the same target. Aiming is easy, because Emberquake has limited seeking and ricochet abilities and it can fly over gaps.
  
• Force Field 15/15
  Main defense skill of the build. Force Field is the most powerful defensive ability in the game, at clvl100-slvl15 it grants a base absorption of ~17000 damage without charge, while a fully charged Force Field grants ~60000 absorption.
  Force Field affects nearby allied players and pets.
  
• Healing Bot 15/15
  Main support skill of the build. Maxxed Healing Bot grants an avarage of ~400HP/sec and ~14MP/sec regeneration. Mana regeneration is very important, because Emberquake costs a lot of mana.
  Healing Bot affects nearby allied players and pets.

Optional skills are all recommended, the player is free to choose any combination of these.

• Immobilization Copter 15/15
  Slows down enemies constantly with a chance to interrupt them, it is one of the most reliable crowd control skills in the game.
  
• Dynamo Field 10+/15
  Only dedicated charge generator skill of the engineer - no, Shield Bash doesn't count -, it is required to fuel Force Field.
  
• Onslaught 5+/15
  Mobility skill that also grants a heavy slow effect on enemies hit, the more points it gets, the better. Stacked with Immobilization Copter, it can slow down most non-boss enemies to ~25% speed.
  
• Fire Bash 15/15
  Fire Bash is one of the two amplifiers for fire damage, the other being Blast Cannon. Fire Bash greatly improve damage done by Emberquake, which does heavy fire damage.
  
• Seismic Slam 15/15
  Seismic Slam is one of the most common skills used in connection to Emberquake. Emberquake's high level requirement inspired players to use Seismic Slam for crowd control and leveling purposes.
  
• Fire and Spark 15/15
  Fire and Spark gives 75% additive bonus to Fire and Electric damage, which equals to 150 additional Focus.

Some skills should be avoided, as they doesn't benefit the build in any way or even worse.

• Sword and Board
  The damage from Sword and Board is off-weapon constant, it doesn't scale properly with any stat.
  
• Shield Bash
  Shield Bash is regarded as a charge generator, however it's underwhelmingly small area of effect makes it close to impossible to hit multiple enemies with it, meaning that it won't generate charge as fast as Dynamo Field does.
  
• Aegis of Fate
  The shield generated by Aegis of Field is limited by the amount of armor the character wears and it is unreliable, making it unworthy of mention. Force Field offers much more than that on will.
  
• Bulwark
  While the physical damage reduction could be useful, all damage reduction will cover that as well in endgame gear and the armor bonus alone is not enough to worth it.
  
• Charge Reconstitution
  Healing Bot covers that, nuff said. Health damage will be a rare occasion with Force Field up, engineers rarely need additional healing and potions can cover that.

Emberquakers are less-reliant on stat enchants, as their damage is overpowering by default, but it doesn't hurt at all to have more.
Some useless statistics are ignored, like execute-chance from focus or armor gain from vitality.

Your goal is to hit the critical hit cap, which comes around ~1000 strength.

• Improves weapon damage and DPS
  Emberquake has a Weapon DPS part, which in most cases ends up to be the minor part of the damage done by the skill, but it is heavy damage nonetheless. Improving it further never hurts.
  
• Improves critical damage
  Emberquake's damage can crit, both part of the damage benefits highly from an increased critical damage. Critical damage is always a multiplicative to other modifiers. Critical damage bonus is the main reason for increasing strength for an Emberquaker.

Your goal is to hit ~300 dexterity.

• Improves critical hit chance
  Critical hit chance is an important part of the formula that makes strength a rewarding investment, the more critical hit chance, the better.
  
• Improves dodge chance
  While many guides highlight dodge as an important defense, it is impossible to dodge the heaviest hitting attacks, meaning that dodge doesn't make any difference for an engineer. On the other hand, the build requires heavy critical hit chance, which brings high dodge chance too.

Your goal is to have the most focus possible.

• Improves magic damage
  Emberquake's fire damage is "magic" damage, increased by focus directly, as the magic damage is the larger part of the whole damage done, focus improves Emberquake's damage greatly.
  
• Improves elemental damage
  Elemental damage done by the weapon gains additional damage from focus. In this regard, focus and strength are additive to each other with elemental damage weapons.

Your goal is to hit block chance cap, which comes at 100 vitality with Parma's Coal-Burner or 399 vitality with shields offering 15% block. If one uses the Mondon's Vestment set and Parma's Coal-Burner, than he doesn't require any point in vitality, as the set alone gives enough vitality.

• Improves block chance
  Emberquake works well with a shield in offhand and shields grant an additional defense line. Vitality offers a bonus to block chance. One should choose a shield and calculate the required amount of Vitality to hit the 75% block cap.

Generally, most players use Mondon's Vestment, a 1hander mace and a shield. Maces offered the best elemental damage among melee weapons before the 1.22 patch, yet in 1.22 the best weapons with purely elemental damage are still maces.

In short, the mainhand's damage largely influence the damage output of Emberquake. Weapons with purely elemental damage get the best bonus from both both strength and focus. Enchanting weapons with elemental damage is quite likely the best way to enchant for Emberquake. On the other hand, Emberquake conveys weapon effects as well. Some of the better mainhands:

• Arcgap's Vice
  Pure electric damage, good one, it's one of the new weapons in the game that came in the 1.22 patch.
  
• Smithereen
  Guaranteed shield breaking and heavy physical damage, it came in the 1.22 patch too. If you have a personal hatred or a holy crusade against shielded enemies, this is your best choice.
  
• Hammer of Offcial Rebuke
  Heavy elemental damage, it was the preferred weapon of most Emberquakers, it's still good, as it is fairly easy to gamble.
  
• Hammer of Retribution
  Heavy elemental damage and while it does less damage than Hammer of Official Rebuke, the 25% chance for Glacial Spike makes up for it.
  
• Shards of Cobalt
  One of the new swords introduced in the 1.22 patch, it is one of the better options.
  
• Axe of the Elder One
  While this one is a bit lackluster compared to others, it's Acid Rain proc can help. Never forget, axes have lower max damage than other weapons, thus, their critical hits are much weaker.

The general shield choice is Old Master Q, but I don't recommend it. When you compare it to other similar level shields, it becomes clear, that Old Master Q is one of the worst choice to build around.
Anything that blocks can work, but I personally recommend Parma's Coal-Burner with it's whopping 45% chance to block. Which is better, 10% all damage bonus equal to 20 Focus or 20% chance to block? Little math:

Old Master Q requires 255 vitality to hit block cap with Blocking VI spell.

Parma's Coal-Burner requires 100 vitality to hit block cap with Blocking VI spell.

Using Old Master Q, you lose 20% block, which in this case means 155 stat point you put into vitality. The character loses 77,5% all damage, but Old Master Q gives 10% all damage. Your overall lose is 67,5% all damage.

Also, Old Master Q is a legendary, an extremely rare drop, while Parma's Coal-Burner is a unique, a relatively common drop that you can gamble easily.

Armor bonuses are irrelevant, as armor doesn't scale well endgame.

Most emberquakers use the Mondon's Vestment set, enchanted for stats, gemmed for damage reduction and even more focus. It's not optimal, but it does the job and it looks good. Aside from these, there is not much to tell about emberquaker gear, your best bet in armor, sockets and enchants is to get the following attributes:

• Damage Reduction up to 50%, to hit the 75% cap with the innate 25% that all engineers have.
  
• Chance to reflect missiles.
  
• Strength and Focus, the more the better.
  
• +X% Health.
  
• +X Health.
  
• Casting Speed, while Emberquake has a cooldown, it helps everything else.
  
• Attack Speed affects weapon DPS, it is a minor damage increase.
  
• Magic finding luck for loot.
  
• Gold finding luck for farming money faster.

Enchant your gear with attributes by Boris, try to get ~150 stat on everything, so that you can hit 1000 strength, ~300+ dexterity and 1000+ focus.

There's not much to say about it, it's a cookie-cutter, nothing complicated.
In most cases you want your Force Field on, having both Healing Bot and Immobilization Copter circle around you.
If something shows up, just spam Emberquake. if it dies, search for something new to whack. If doesn't die, spam even more Emberquake. You can jump around with Onslaugh, but you don't really have to. Also, don't forget to spam Emberquake.

Again, there's not much to say about tactics, as this is a cookie-cutter, just don't forget to spam Force Field and Emberquake, if you can, you should generate charge with Dynamo Field before using Force Field. Also, don't forget to spam Emberquake.

Any guide on Steam ends with the previous section, because most of the time, authors forget that there is no perfect build.
Above, the default Emberquaker is discussed, there's no need to talk about that. We want to improve it!
Emberquakers work pretty good without any further improvement, but out-of-the-box thinking never hurts! Especially in the case of Torchlight II and it's predecessors. Most of the engineer players want the very best they can squeeze out of their favourite toon.

Emberquake is a sophisticated cookie-cutter, the skillset has no major flaws, I had a hard job at improving it in any way. The main skills are mandatory and have not much competitor, the only way to improve the base build is choosing the right optional sklls.

• Emberquake
  Emberquake has only one competition, Flame Hammer. While Flame Hammer's splinters won't convey weapon effects and they do inferior damage, charged Flame Hammer releases a lot more splinter. Endgame, the damage potential hardly evens out with charge usage.
  
• Force Field
  Force Field has no competition, the closest thing in the game offers only a fraction of the same defense with a chance to not activate at all. You can't improve your defense further through skills.
  
• Healing Bot
  Healing Bot also has no competition, engineers have no other skill that generates mana.
  
• Fire Bash
  Fire Bash is a rare sight in Emberquaker builds and I don't know why. Emberquake's damage is mostly pure fire, increasing that by 50% never hurts. If you have a shield, don't forget to max Fire Bash!

Emberquake builds have lots of stat plans. It was the worst before the 1.22 patch, as elemental melee weapons were quite rare. Most common stat plans are pure Focus and pure Strength, both works, but neither is perfect.

• Pure Focus
  It's flaws are obvious, the critical hits do underwhelming damage and it's close to mandatory to use an elemental melee weapon with it. It was considered to be the best stat plan until some players started calculations on the mechanics of Emberquake.
  
• Pure Strength
  Another stat plan with flaws. critical hits will hit for slightly more damage, but the base damage is reduced in the process.
  
• Enough Strength to hit critical damage cap and rest in Focus
  Calculations indicated, that in fully enchanted endgame gear, Strength beats Focus until the character hits critical hit cap, after that, Focus increases the base damage better. With the 1.22 patch, highend elemental melee weapons came, giving the players the required simplification in the damage formula.

Stat Distribution until hitting lvl100 should be something straightforward in order to equip gear earlier. In short, starting equipment of an Emberquaker should be a unique one-handed mace of a decent level and at some high level rare items with attribute bonuses.
Hammer of Retribution is one of the best weapons and it is relatively easy to gamble for, making it an ideal guideline.

• Strength
  Hammer of Retribution requires 186, that should be guideline while leveling.
  
• Dexterity
  While Emberquakers need fairly high dexterity to increase critical chance, most of it will come from enchants.
  
• Focus
  Again, Hammer of Retribution serves as a guideline, it requires 104 focus.
  
• Vitality
  Emberquakers often use shields as described in this guide, but the required vitality heavily depends on the choosen shield. My personal preference, Parma's Coal-Burner has a block chance of 45%, it caps with ~100 vitality and a Blocking VI spell.

This could be translated to a 2-0-1-0 with 2 spare point each level, but I'd recommend 3-0-2 until ~lvl60, that way the character can equip weapons earlier.

While the skillset and the right stat distribution is only a minor tweak on the Emberquaker, the right mainhand weapon can improve it heavily. In the beginning, Emberquakers choosed the highest DPS, it still happens most of the time.
On the other hand, Emberquake has the potential, to deal even higher damage with spell trigger chance or DoT stacking, which leads to this part.

Mainhand is the key of many builds, one can approach the build in many ways, I'll list the more important ones.

The old-fashioned way to choose mainhand is choosing by the DPS it is capable of, preferring high elemental damage. Elemental damage weapons gain advantage of both high Strength and Focus scores. Some of the new legendaries introduced in the 1.22 patch can do quite heavy elemental weapon DPS, comparable to Emberquake's innate magic damage.

Arcgap's Vice, Shards of Cobalt and Axe of the Elder One all work, Arcgap's Vice being the best without question. Smithereen is also a good choice for it's immense physical damage and utility.

Critical strike chance is the best way to socket them as it improves both magic and weapon DPS overall, but attack speed and pure physical damage can work too. Gems to look out for: Skull of Whorlbarb, Skull of Vastok and Vellinque Skull.

One can try spell-trigger build, which improves the damage better than high weapon DPS does. Glacial Spike immoblizes foes and does ~7000 base damage at lvl100, Meteor does similar damage in avarage. They have low chance to proc, but their damage makes up for it.

Arcgap's Vice is again one of the best choices, but Hammer of Retribution beats it without doubt with it's incredible 25% chance to cast Glacial Spike. Hammer of Retribution is still one of the best choices for any Emberquake as it was before the 1.22 patch.

Glacial Spike, Meteor, Thunder and possibly Lightning are good procs on both weapon and socketable. Gems to look out for: Eye of Aleera, Eye of the Dragon and Yellow Basilisk Eye.

One can try stacking damage over time in the mainhand weapon, it works well, because Emberquake is one of the best skills for DoT stacking. Because this approach concentrates on physical damage over time it's recommended to use Ember Reach and Tremor in the build to increase the damage output. Using a DoT build one should concentrate more on Focus.

Any ilvl105 unique 1hander works well, as they all have 4 sockets, but Netherrealm Hammer looks better than the others and it has some innate damage over time as well.

Sockets are the soul of this approach, Zardon's Mighty Skull and DoT Blood Embers are the ones to look out for.

Offhand should be a shield, as Emberquake doesn't require an offhand weapon to be effective. Choosing a shield is an important part of the build, it determines the required vitality to hit the 75% block cap. It is common mistake is to choose Old Master Q over the better shields, so I'm providing some examples:

• Parma's Coal-Burner
  Parma's Coal-Burner is a relatively easy-to-get, high-end shield which does the thing we expect from it: blocks. It's whopping 45% chance to block is quite impressive, you won't need hundreds of vitality to reach the block cap with it. Also, it is fairly easy to equip at low levels if you already have one.
  
• Escutcheon
  It grants heavy health and mana regeneration and the highest damage reduction based on the number of monsters around. It's unique bonuses make up for it's underwhelming block chance.

This is my first finished guide, it took my whole day to write it and on top of that, also dozens of gameplay hours were invested in the character I used to to try and test my build ingame.

Have fun and if you liked this, stay tuned for more!