The Sapper is a combat engineer, they assemble battlefield impliments to aid allies, and twart enemies. The sapper uses many existing skills but expands on their use, most notably wards and item spells.
Constructs
The most unique aspect of the sapper is their ability to assemble constructs, these are autounamous mechancial devices (much like Asuran Golems), some are offensive, some defensive. What sets constructs apart from spirits and minions is their ability to use skills (and thus energy as well), every construct has one attack or defensive skill always available to them, additional skills become available to Constructs by skills available to the Sapper.
Roles: Supporter/Disabler
Stats
Armor: Caster (60 AL)
Energy: Caster (30 w/4 pips of regen)
Weapon: Caster (wands/staves)
Armor Insignias
Mechanic's: Reduces the activation time of Construct Skills by 25% (non-stacking)
Construct’s: Armor +5 (while you control 1 or more Constructs)
Armor +5 (while you control 3 or more Constructs)
Armor +5 (while you control 5 or more Constructs)
Defender's: Armor +10 (while you are within a ward)
Eccentric’s: Armor +5 (while recharging 1 or more skills)
Armor +5 (while recharging 3 or more skills)
Armor +5 (while recharging 5 or more skills)
Attributes
Engineering (primary): Deals mostly with skills that improve the effectiveness of Constructs, and other skills. For every rank in Engineering Constructs and Wards last 2% longer. Increases the number of Constructs you can control at one time (maximum of 6).
Construction: Deals with offensive constructs and abilities.
Fortification: Deals with defensive connstructs and abilities.
Sabatoge: Deals with skills the thwart, disable, and damage enemies.
Sample Skills
Engineering
Mechanic’s Fervor [Elite]:10E 1/4A 45R Stance; For 3…20 seconds your skills activate 8…50% faster and you cannot be interrupted.
Elemental Shielding: 5E 1A 20R Enchantment Spell; For 5…30 seconds target Allied Construct gains +20 armor against elemental damage.
Battery Drain: 5E 1A 25R Spell; Target Allied Construct loses 8 energy, you gain 1…14 energy
Mechanized Assembly: 10E 2A 30R Enchantment Spell; For 10…45 seconds all your Construct Skills recharge 30% faster.
Repair: 10E 2A 8R Skill; Target Allied Construct is disabled for 5 seconds, while disabled the Construct gains +40 armor and 5…30 health per second.
Construction
Iron Hound: 10E 3A 30R Construct Skill; Create a level 1…18 Iron Hound which dies after 30…120 seconds. Iron Hounds use "Hound's Bite" an attack that damages foes and causes deep wound on knocked down foes.
Assault Dryder: 25E 3A 30R Construct Skill; Create a level 1…18 Assault Dryder which attacks from range. Assault Dryders use "Serated Bolt" an attack which damages foes and causes bleeding. The Assault Dryder dies after 30…120 seconds.
Siege Ballista: 15E 5A 45R Construct Skill; Create a level 1…18 Siege Ballista which is immobile and its attacks affect its target and all adjacent foes. Siege Ballistas use "Unleash Hell" a preperation which causes it's attacks to inflict burning. The Siege Ballista dies after 30…120 seconds.
Siege Exoskeleton [Elite]: 25E 2A 30R Elite Form; For 10…58 seconds, you gain +25 armor and your attacks deal +5…20 fire damage. This skill is disabled for 120 seconds.
Zealous Construct: 25E 5A 45R Construct Skill; Create a level 1…18 Zealous Construct, every time a Zealous Construct uses an Attack Skill you gain 1 energy. The Zealous Constructs use "Static Burst" a skill which interrupts and damages all adjacent foes. The Zealous Construct dies after 30…120 seconds.
Adamantine Spear: 10E 1A 10R Skill; For 5…17 seconds all your Constructs gain the Adamantine Spear attack skill, Adamantine Spear strikes from range for 5…41 damage and has 10% armor penetration.
Fortifications
Power Generator: 25E 1A 45R Ward Spell; Set up a Power Generator at your location, for 5…17 seconds all non-spirit allies in its area gain 1..2 energy regeneration.
Sentry of Flame: 10E 5A 20R; Construction Skill; Set up an immoble level 1...8 Sentry of Flame at your location all allies within its area gain +5…15 armor against fire damage and Sentry of Flame deals 5...15 fire damage to 1 foe in it's area every 2 seconds. Sentries of Flame use "Elemental Capacitors" a stance which allows them to gain health while taking elemental damage. The Sentry of Flame dies after 20…60 seconds.
Ether Barrel: 15E 2A 25R; Item Spell; Create an Ether Barrel, hold it for up to 10..23 seconds, while holding the Ether Barrel you gain +1 energy regeneration. When you drop the Ether Barrel all nearby allies gain 4…12 energy.
Barricade: 5E 3A 10R; Ward Spell; Create a barricade at your location, for 7…17 seconds all non-spirit allies in its area have a 15…50% chance to block ranged attacks.
Razor Wire: 5E 3A 15R; Construction Skill; Create an immoble level 1...8 length of razor wire at your location, creatures passing through the razor wire become crippled and begin bleeding for 5..17 seconds. Razor Wires use "Vampiric Barbs" an enchantment which gives them healt when they inflict conditions. The Razor Wire Dies after 20…60 seconds.
Sabatoge
Foo Gas [elite]: 10E 2A 15R; Item Spell; Create a barrel of Foo Gas, hold Foo Gas for up to 13…35 seconds once dropped Fu Gas detonates after 3 seconds, dealing 10…85 damage and burning to all nearby foes.
Jadite Explosive: 5E 2A 20R; Trap; When Jadite Explosive is triggered all nearby foes are struck for 5…32 damage and suffer from cracked armor for 10 seconds. Jadite Explosive automatically triggers after 90 seconds. While activating this skill you are easily interrupted.
Grappling Hooks: 15E 1A 45R; Spell; Target foe is struck for 3…17 damage, is knocked down and teleported to your location. This Spell has half the normal range.
Powder Keg: 5E 1A 8R: Item Spell; Create a powder keg, hold the Powder Keg for up to 10…24 seconds, once dropped Powder Keg detonates after 3 seconds, dealing 5…32 damage to all nearby foes.
Energy Trap: 10E 2A 10R: Trap; When Energy Trap is triggered all nearby foes are struck for 5…17 lightning damage and lose 2…12 energy. Energy Trap is automatically triggered after 90 seconds. While activating this skill you are easily interrupted.
Decoy: 5E 2A 10R: Construct Skill; Create a level 1…8 Decoy at your location, when the decoy dies all nearby foes are struck for 10…72 damage and become dazed and crippled. The Decoy dies after 20...60 seconds.
Precise Charge: 5E 1/2A 8R Spell; Strike target foe for 9…47 damage, if that foe was suffering from cracked armor Precise Charge deals an additional 5…52 damage.
Vial of Nitrous: 10E 1A 5R Spell; Send out a Vial of Nitrous at target foe. Vial of Nitrous deals 9…65 damage to all adjacent foes.
Hope you like it
EDIT:balanced some skills and updated some descriptions. Thanks for the feedback!

My first time writing up this many skills but, the sentry was intended to only have ward range, still rediculous damage though...hmm maybe it should incorperate a defensive spirit type thing "every time Sentry of Flame deals damage in this way it looses X health" or something? That and turn it down so it only damages once every few seconds rather than every second