This build features base 50% Necrotic penetration from passives and affixes as well as -25 resists on enemies from marked for death by Sigil of Mortality 1/1.
Damage breakdown is as follows for melee:
(100% Crit Chance x 3.3% damage) Harvest X ~3000% damage modifiers from Death Seal and Reaper Form X ~600% melee critical strike multiplier when using Suloron's Step and Death's Embrace.
Titan Heart is an all rounder for the build.
The only strategies while playing this build are to avoid area attacks from monsters and bosses while using Death Seal for damage, armor scaling, and stun avoidance (Corrupted Consciousness ,Desperate Shroud).
Aura Of Decay Applies additional Armor shred (Decrepify) to enemies in conjunction with Bone Curse (Defile Defenses) while also keeping you in Reaper Form longer with the Absence of Life node.
Harvest does double damage to cursed targets which becomes 2.65 with the Symbol of Loss 5/5 node. Spectral Whetstone 3/3 and Iron Mouths 3/5 puts Harvest base crit to 39%. You have base 5% and the passive Deathbringer 5/5 gives you Increased 50%. Reaper Form ,Reaper's Curse 4/4 Gives you another 100% increased critical strike chance, so your total crit chance with Harvest ends up being (44% increased by150%) =110%.
200% is the base critical strike multiplier. You gain 50% from the passive Clairvoyant Insight 5/5 and another 50% from Reaper Form, Executioner 5/5. This puts you at 300%.Now add the Death's Embrace and Suloron's Step to get a total critical strike multiplier for melee attacks up to a minimum of 420%.