Hello, and welcome to my build! This is still a bit of a work in progress, but when you get the procs right, it hits like a ton of bricks. If you like this, feel free to drop a like and check out some of my other PvP and PvE builds.
Attributes: With the heavy armor passives, we get a good health pool. Put 5-10 points in health, and you should be good. As a general rule, you don't want more health than about 30K.
With two heavy pieces, you will notice lower damage. If you want more DPS, you can swap to five body pieces of Mechanical Acuity, but you will be squishier. I prefer having the heavy armor, but it's a personal preference. For jewelry enchants, health recovery is good. If you want more damage, switch that to increase magical harm or to increase magicka recovery, if you need more sustain. Feel free to experiment.
One quick note on the monster helm: Balorgh is a really nice set to have, but it does require you to get lucky with the Golden Vendor, or to clear vet March of Sacrifices. If you're not able to get that, Slimecraw is a good alternate. Earthgore can be good, if you want stronger healing. Engine Guardian too, if you have sustain issues.
Backbar weapon: I prefer running a resto staff for Combat Prayer, but you can experiment here. BRP daggers, DSA sword and board, BRP resto staff are all good options, just slot the appropriate ability in the Combat Prayer slot. Backbaring a Mara's Balm staff gives bonus armor, which is nice to have.
Fight Rotation:
Prebuff with Siphoning Attack and Combat Prayer (for minor berserk). Merciless Resolve no longer needs to be prebuffed.
Open the fight with Reaper's Mark, light weaving after each attack. (1LA)
Next, hit them with Debilitate. (2LA)
Then, open up with your spammable, use it twice. (4LA)
At this point, you're ready to start your killing damage burst. Hit them with your ultimate to proc Balorgh. (Casting this at full ultimate will give you 500 additional spell damage and 11,500 {23x500} spell penetration) After you light attack (5LA), this will proc the Spectral Bow from Merciless Resolve. Fire that off, then follow up with Impale.
When I tested this on a trial dummy at max Ultimate, I critted on all three abilities and did 49K damage on Soul Harvest, 73K on Assassin's Will, and 17K on Impale, for a total of 139K over about three seconds.
With full ultimate and full stacks of Mechanical Acuity, this has maximum penetration and great spell damage.
One important note: Balorgh's proc is based on total ultimate, not ability cost. You'll notice you hit much harder with 500 ultimate than with the 70 ultimate minimum needed for Soul Harvest.
If you prefer to maximize your range and stay away from enemies, you can swap Soul Harvest for Shooting Star.
Backbar Healing Rotation:
If you're getting hit hard, swap to the backbar. Here, you get major protection (10% damage reduction) passively from Blinding Flare. Cast Healthy Offering, this give minor mending, an 8% healing increase. Follow this up with Dark Cloak, for minor protection, (5% damage reduction) and healing over time. Finally, cast Combat Prayer. This gives a great burst heal, buffed by minor mending, and minor berserk. If you have the ultimate, you can also chose to cast Light's Champion, for a ton of passive healing and major force, a 20% increase to critical damage. This will also proc Balorgh. Now swap to the frontbar and slay your enemies!
Do note that this is an optimize rotation. If you get ganked, you might have to roll dodge and spam Combat Prayer until you can stabilize before doing anything else.