The greatest thing about Torchlight II is the ability to customize your skill set to your own liking and have it be viable toward higher difficulty levels. However, I am going to introduce a build that is both powerful yet engaging to play. Your ability to micromanage your minions and skills will determine your success in elite difficulty.
The foundation of this build rests on the ability to debuff or weaken enemies to fire damage and physical. As such, this build synergizes well with fire embermages, beserkers, and melee engineers while keeping essential skills to benefit co-op play. I hope you enjoy playing.

Strength: Half your points go into this. You won't be solely relying on your cannon to do damage; however higher strength will enable you to equip better armor, which given the lack of a shield is essential.

Dexterity: No points in this. Some of you may be surprised, but as I said above, your damage output does not only consist of your cannon, therefore points are better spent elsewhere.

Focus: None. It might be tempting to put points here, but the fewer points placed in focus, the greater your character will be near the end of the game.

Vitality: The other half of your points go here. It is important to note that cannons require on a vitality requirement, therefore higher vitality will allow you to equip better cannons even without meeting the level requirement.

Healing Bot 10
This skill is essential to this build and most engineer builds. You do not, DO NOT have to max this. Near level 50, your character basically will not need potions anymore as this skill, combined with a strengthened Forcefield allows your HP and Mana to regenerate such that you can safely use skills with impunity.

Blast Cannon 15
This is your primary skill, always have it on right click. The beauty of this skill is the secondary effect of increasing physical and fire damage taken by the enemy. Combined with Spider Mines, which deals both fire and physical damage, your character is quickly able to bring bosses to their knees.

Spider Mines 10
Most people are under the misconception that it is necessary to max this skill. More points invested in this skill does not in any way increase the damage done, but decreases the cooldown time, and increases the summon duration, allowing one to summon more minions at any given time. Because of the setup time involved and the use in an actual boss fight, as long as the cooldown is sufficiently short enough to allow you to run and occasionally cast Spider Mines is enough. Therefore, at a cooldown of 2.1 seconds, you will already achieve nearly maximum efficiency with this skill.

Gun Bot 15
This skill doesn't need much explanation. The reason why both Gun Bot and Sledgebot are needed is that having more minions means that less of the enemy is focused on you, allowing more freedom to run around and firing Blast Cannons and Dynamo Field.

Sledgebot 15

Forcefield 15
Your second most useful skill that will save you many a death, have this on right click as well. The usefulness of this skill cannot be taken lightly. Even at level 1, this skill is still incredibly useful because any hit, regardless of how strong it is, will be blocked by Forcefield. Even near late-game, the amount of damage absorption by Forcefield is ridiculous.

Dynamo Field 15
This is your only skill that gains Charge, and it does that well. Forcefield receives a massive buff for each Charge acquired, therefore this skill is an absolute must to realize the potential of Forcefield. At higher levels, when attacked by an enemy mob, your Charge will rapidly be filled. The inherent danger to this is, of course, that you actually have to be fairly close to an enemy to gain charge. This danger can be somewhat mitigated by Tremor, but still requires the player to think carefully in what situations to attempt to gain Charge. For instance, in co-op play, your Forcefield becomes invaluable to your party, so by having the monsters focus on other players, you can assist by gaining charge and casting Forcefield.

Tremor 15
Since your skills aren't casted very fast, it becomes necessary to have a skill in your arsenal that allows you to escape a tight situation and find a safer location to fight. Tremor has a very large range and decent knockback and is much better than Seismic Slam for that purpose. When maxed, this skill makes it that much easier to acquire Charge, with that 2 second stun inflicted on all enemies within 24 meters. It is worth noting that this skill has the largest radius of effect for any skill for all characters. Seismic Slam's radius is less than half of this.


Immobilization Copter 1
You don't have to get to Tier 1 to see the usefulness of this skill. One point is enough to hinder larger monsters, giving you more time to dodge their attacks.

Heavy Lifting 5
At level 5, you receive a 10% increase in Attack Speed, which is sufficient because you will be casting Spider Mines nearly as often as you will be attacking with your cannon.

Bulwark 5
A nice bonus to armor and decrease in physical damage. The disadvantage with placing excess points into this passive is when the need arises for this passive you would be one-hit KO'd anyways, so a 15% reduction in damage isn't going to help much at all.

Charge Domination 1
Always nice to be able to fill your Charge bar without much effort. One point is more than enough.

Total Points: 122

You should be left with 10 additional points that may go anywhere depending on your needs. If you find yourself dying too often, place points into Bulwark and Charge Reconstitution or Heal Bot. If you want to deal out more damage, place points into Heavy Lifting, increasing your weapon DPS. For greater crowd control, add points into Immobilization Copter.

Cannon: Honestly any cannon with around 500+ DPS is fantastic for late-game. Acquiring a Legendary is even better, but there are several uniques that can compete in terms of damage. Socket with a "-X Armor on Hit" and you are golden.

Armor: Preferably with an increase in pet/minion damage modifier as well as mana recovery per second.

Miscellaneous: Equip a weapon that decreases pet travel time. The only one I've seen is a Level 76 unique Dragon's Claw sword, which decreases pet travel time by 60%. Combined with the spell Animal Handling, another 40% reduction, you are looking at a 1 second pet travel time!


Spells: The disadvantage to having a large skill arsenal is the lack of space on your hot-key bar for spells. To this end, passive spells such as Adventuring, Animal Handling, Barter, and Concentration are preferable; your pet should be equipped with at least 1 attack spell (Frost, Fireball, or Roller), 1~2 summons (Summon Archers, Summon Skeletons, et cetera), 1 debuff or buff (Silence, Elemental Overload, et cetera).

A basic strategy when you enter a new area is to cast Heal Bot, Immobilization Copter, and Forcefield right off the bat. Then based on the number or strength of enemies, summon either Gun Bot or Sledgebot or both to have minions that assist you in dealing damage. You should be fairly consistent with Spider Mines, casting them every so often as you walk if entering a dangerous or unexplored area. If you encounter strong enemies, use Dynamo Field to gain charge and recast your Forcefield often. The attack pattern is simply maintaining distance away from enemies while alternating casting of Blast Cannon and Spider Mines.

Minions!

Tremor's radius