This is probably the fastest TX13 build for Necro, capable of doing 2 min T13 runs on a regular basis (and certainly sub 2min with decent density or pylon luck). And it's also super easy to play like LazyNecro should be played. Can be also used for bounties, then i recommend Warzh bracers instead of Nemesis.
If you have mousewheel that you can click, then you don't need the keyboard at all to play. You move with holding LMB, fire occasional Bone Armor with RMB and blood rush with mousewheel click.
LotD and Simulacrum are occasional and only real use for Rift Guardian. just pop them for pretty much instakill, especially if you catch Physical CoE phase. You can even use manual cast with just clicking these two skills on your hotbar with your mouse.
NB! aura on Left mouse button is imporant, as these skills are not "clickable" and therefore game takes it like Force Move action.
For clarifications: how this build works.
- If you have at least one stack of Bone Armor active with Inarius 6-piece set bonus, you'll gain 15 yard radius autodamage aura. The aura itself does little to no damage (doesn't get bonus from 6pc too!). Also refreshing Bone Armor itself too often is not that important, as it's damage is not too great. Best to do it while cold CoE phase is active or say with every elitepack. I tested it deeper and the aura does 2 ticks per second and each can crit. The behaviour of the aura damge is tick-tick-pause-tick-tick-pause: two ticks with just 0,2 sec between and then about 1 sec pause. It's attack speed unaffected. Any Bone Armor Skill bonus is wasted stat. Of course you want to have max 15 stacks (pretty much given, if you're bit careful from the start), because you'll get much higher damage reduction from Kalan amulet and little bit bonus movespeed too.
- autodamage applies Toxin gem and can (if it crits) apply Pain Enhancer gem. It's really important to stack critical hit chance to have higher chance to apply PE, as it's majority of the damage.
- Your Aura of Frailty will apply autocurse for every enemy within 15 yards (besides killing anything below 15% HP). This will give you damage bonus for Trag Fang and damage reduction for Dayntee's belt. Eternal Torment passive ensures that any monster you curse, will stay Frailty cursed for at least around 3 screen range.
- For Inarius damage bonus: you have to start dealing damage within 15 yard (this tornado range), but you'll keep damage bonus for Damage over time effecets even if monsters leave the range for 3 seconds (in-line with Pain Enhancer).
So TL;DR, you move through any mob, the get cursed (fang, daintees), slowed (slow time) for complete BoTT gem uptime and Krysbin first part (100% dam increase), applied DoT-s to them (PE/Toxin) and all this DoT damage gets multiplied by many factors (reilena's . For RG-s you can add simulacrum (double damage with Reilena's as it'll double your Essence pool) and full krysbin (300%) with Land of the Dead. You'll get some full 300% Krysbin thruough rifts too (from enchantress and speed pylon for example), but it's not that reliable. Also, with autoconsume from Devour/fueled by death and autoslow from lost time you'll get tons of movespeed. And then you add steuart boots for insane movespeed.
And that's it, you dont cast any skills (except Bone Armor refresh) manually, you just move through mobs and you deal automatic passive, aura-like damage. Damage that's greatly amplified multiple damage bonuses (6pc set, BoTT, krysbin, fang, reliena, CoE, etc).