A Lacerman (stolen) + Soulthirst theorycraft.

STEP BY STEP LEVELLING: Act 1: Buy Frost Blades from Nessa after you kill Hillock. We're going to use Frost Blades for clear and Double Strike for single targets. Buy a Paua Amulet for mana regeneration(we will need this until we get Life and Mana Leech on passive tree) and also craft movement speed boots as soon as you can. Pick up 3-colored items and sell them for chromatic orbs for first 2-3 acts. We will need them since we change skills through levelling. Keep on upgrading mana flasks especially until Act 6, we will be using them frequently. Also Magic weapon with added Physical Damage mod recipe will be handy(1 axe, 1 magic or rare Rustic Sash, 1 Blacksmith's Whetstone). Explore every Vaal side area in search of Vaal Ancestral Warchief, also use Vaal orbs that drop on Ancestral Warchief gems to get it. Get Quicksilver Flask and Onslaught Support after Mercy Mission quest, also buy Ruthless and Ancestral Call from Nessa. Link Onslaught and Ancestral Call with Frost Blades, also Ruthless with Double Strike. Get Dash, War Banner and Ancestral Protector after Breaking Some Eggs quest. We will be using Ancestral Protector on bosses. Also get Blood and Sand and start levelling it in second weapon set(or somewhere on gear). Use Dash coupled with Quicksilver flask for movement. Get Leap Slam and Maim after The Caged Brute quest. Link Maim with with Double Strike. Change Leap Slam with Dash and keep on using Quicksilver Flask as a support. Get Lacerate after Siren's Cadence quest and start levelling it in second weapon set(or somewhere on gear). Make sure your level is 13 and life is 250 or higher before killing act boss. Act 2: Try to get Life and Mana Leech first on passive tree here. Start by going right to Old Fields to do Intruders in Black quest. Get Blood Rage, Herald of Purity and Flesh and Stone after Intruders in Black quest. Keep Flesh and Stone in Sand Stance while clearing and Blood Stance while bossing. Drop War Banner. Get Faster Attacks, and Melee Physical Damage after Sharp and Cruel quest. Link Faster Attacks with Leap Slam and change Melee Physical Damage with Maim on Double Strike. Keep levelling Maim in second weapon set(or somewhere on gear). Here, also get another Melee Physical Damage and Close Combat and level these in second weapon set(or somewhere on gear). Make sure your level is 19 or 20 and life is 500 or higher before killing act boss. Act 3: Get Dread Banner and Pride and start levelling them in second weapon set(or somewhere on gear) after Lost in Love quest. Here get a Praxis unique ring if having mana issues, which you normally shouldn't. Get Bladestorm after Sever The Right Hand quest. At level 28, switch from Frost Blades to Bladestorm with adding Close Combat and Melee Physical Damage support that were levelling in second weapon set(or somewhere on gear) and also Onslaught as 4th link. From now on, playstyle will have to change a little from shooting enemies at short distance to firing while being at the center of everything. But no worries, Bladestorm is even easier than Frost Blades. Buy Arctic Armour from Act 2 and start levelling it in second weapon set(or somewhere on gear). Make sure your level is 29 or 30 and life is 700 or higher before killing act boss. Act 4: Get your second 4-socketed item, put Double Strike there and add Maim you were levelling in second weapon set(or somewhere on gear). Get Multistrike, Brutality and Multiple Totems after The Eternal Nightmare quest and level them in second weapon set(or somewhere on gear). Do normal lab before killing final boss. Also make sure your level is 35 or 36 and life is 1.0k or higher before killing act boss. Act 5: At level 38, buy Vaal Ancestral Warchief from trade site and change it with Double Strike. If you checked every Vaal side area and used Vaal orbs that drop on Ancestral Warchief gems, you might have it until now. Link it with Multiple Totems, Ancestral Protector and Maim. From now on, we'll be using both Vaal Ancestral Warchief and Ancestral Protector on bosses and then Bladestorm them. If you don't have or can't buy Vaal Ancestral Warchief yet, get regular Ancestral Warchief instead and link it with Multiple Totems. You can buy Vaal Ancestral Warchief later. Get Silver Flask after The Key to Freedom quest and replace it with Quicksilver flask(we won't need this anymore as leap speed is fast enough), also replace Onslaught with Brutality on Bladestorm. Once you get Slaughter node from passive tree, change Silver Flask. Make sure your level is 40 or 41 and life is 1.4k or higher before killing act boss. Act 6: Change Pride and Blood and Sand you were levelling with Herald of Purity and Flesh and Stone, also add Dread Banner you were levelling in second weapon set. Stay in Sand Stance while clearing and Blood Stance while bossing. Buy Increased Duration and link it with Blood Rage. Don't forget to have %50 or more fire resistance as we'll mostly get fire damage this act. Prepare to Leap Slam the whole act as not much levelling is needed here. Change minor god in Pantheon to Ryslatha after beating Puppet Mistress. Make sure your level is 44 or 45 and life is 1.6k or higher before killing act boss. Act 7-8: Try to buy Haemophilia gloves if you can before getting to level 50. This is the first unique item we need. You can buy it later on if short on currency, no problem. Make sure your level is 49 or 50 and life is 1.8k or more before killing Act 7 final boss. Before starting Act 8, make sure you have 2 good rare axes or craft them. Make sure your level is 54 or 55 and life is 1.8k or more before killing Act 8 boss. Pick Solaris as major god after beating Act 8 boss. Act 9: Do Cruel Lab. Change Bladestorm with Lacerate you were levelling. Change Close Combat with Multistrike you were levelling. From now on, it's time to Lacerate! Our play style is going to change a little. From now on, we'll be shooting at things from distance instead of being in the middle of everything and firing. I suggest watching Defiled Cathedral video one time before switching to Lacerate if you haven't used it before. Make sure your level is 58 or 59 and life is 2.4k or higher before killing act boss. Act 10 and after: Get Sulphur Flask after Safe Passage quest. Make sure your life is at least 2.6k or higher before killing it. After killing Kitava, get gems for CWDT setup from Act 6 and start levelling them to specific levels CWDT(3)+Immortal Call(5)+ Vulnerability(7)+Increased Duration(max) and stop levelling at those levels. Also leave Lifetap support at level 1 to be able to gain Lifetap. Also get Endurance Charge on Melee Stun support for Leap Slam. Add Impale as 5th gem to Lacerate and Fortify as 6th gem. Don't forget to overcap your resists to 109 for Elemental Weakness map mod. Also make chaos resist at least %0. Better if around %30. GEM LINKS WHEN LEVELLING: Act1 End: GGR: Frost Blades + Onslaught + Ancestral Call GRR: Double Strike + Maim + Ruthless Others: War Banner, Ancestral Protector, Leap Slam(Dash) Act 2 End: GGR: Frost Blades + Onslaught + Ancestral Call GRR: Double Strike + Melee Physical Damage + Ruthless RG: Leap Slam + Faster Attacks Others: Blood Rage, Flesh and Stone, Herald of Purity, Ancestral Protector Act 3 End: RRGG: Bladestorm + Melee Physical Damage + Onslaught + Close Combat GRR: Double Strike + Melee Physical Damage + Ruthless RG: Leap Slam + Faster Attacks Others: Blood Rage, Flesh and Stone, Herald of Purity, Ancestal Protector Act 4 End: RRGG: Bladestorm + Melee Physical Damage + Onslaught + Close Combat GRRR: Double Strike + Melee Physical Damage + Ruthless + Maim RG: Leap Slam + Faster Attacks Others: Others: Blood Rage, Flesh and Stone, Herald of Purity, Ancestral Protector Act 5 End: RRRG: Bladestorm + Melee Physical Damage + Brutality + Close Combat (Onslaught moves to Silver Flask here until we get Slaughter node on Passive Tree) RRRR: Multiple Totems + Vaal Ancestral Warchief + Ancestral Protector + Maim RG: Leap Slam + Faster Attacks Others: Blood Rage, Flesh and Stone, Herald of Purity Act 6 End: RRRG: Bladestorm + Melee Physical Damage + Brutality + Close Combat RRRR: Multiple Totems + Vaal Ancestral Warchief + Ancestral Protector + Maim RG: Leap Slam + Faster Attacks GR: Blood Rage + Increased Duration Others: Blood and Sand, Pride, Dread Banner Act 9 Start: GRRR: Switch to Lacerate with links Melee Physial Damage + Brutality + Multistrike(colors are same).