Combat leveling order 18/33/0
Assassination: Malice 5, Ruthlessness 3, Improved Slice and Dice 3, Relentless Strikes 1, Lethality 5, Cold Blood 1
Combat: Improved Eviscerate 3, Improved Sinister Strike 2, Deflection 3, Precision 3, Endurance 2, Riposte 1, Improved Sprint 1, Flawless Execution 1, Dual Wield Specialization 5, Blade Flurry 1, Hack and Slash 5, Weapon Expertise 2, Aggression 3, Adrenaline Rush 1
The 10–30 order, then the Combat core and the Assassination dip of the 18/33/0 level-60 build. Alternatively, take Precision before Deflection, and detour into Camouflage and Master of Deception at 31–38 for easier stealthing. With the Talented legacy perk every step comes up to five levels sooner.
Combat, level 30 0/21/0 Tested in beta
Combat: Improved Eviscerate 3, Improved Sinister Strike 2, Deflection 3, Precision 3, Endurance 2, Riposte 1, Improved Sprint 1, Flawless Execution 1, Dual Wield Specialization 4, Blade Flurry 1
The 15th point goes in Improved Sprint or Lightning Reflexes; either is filler. Alternatively, take Puncturing Wounds for Backstab instead of Deflection and Riposte. With the Talented legacy perk, the extra points go into Hack and Slash. Order: the Combat levelling order above, keeping this build's talents.
Combat, level 60 (projected) 18/33/0 Guide's pick, untested
Assassination: Malice 5, Ruthlessness 3, Improved Slice and Dice 3, Relentless Strikes 1, Lethality 5, Cold Blood 1
Combat: Improved Eviscerate 3, Improved Sinister Strike 2, Deflection 3, Precision 3, Endurance 2, Improved Sprint 2, Flawless Execution 1, Dual Wield Specialization 5, Blade Flurry 1, Hack and Slash 5, Weapon Expertise 2, Aggression 3, Adrenaline Rush 1
The "Sinister Strike" 18/33/0. A popular variant is the same with Lightning Reflexes instead of Deflection. Beta theorycraft: nobody can test 31+ yet. Order: the Combat levelling order above, keeping this build's talents; Improved Sprint, which that order skips, go in where the tree allows.