Venomort - Lv.120
A single Viper pet is capable of killing any unit in the game without breaking a sweat. You're permanently invisible, you have a dozen Vipers, and they all fly through walls.
TO MICRO THE VIPERS LIKE A PRO: In the Dota 2 options menu, go to Hotkeys -> Advanced Options. Bind the movement command "Select All Other Units" to V. When directing your Viper swarm, quickly press V -> A -> LeftClick to make them attack everything they see when moving toward that destination. Then press F1 to return focus to Venomort. You can double-tap F1 to center the camera on Venomort.
Moon Shard's glorious Sapphire effect ensures that your Viper-printing ult, and your invisibility-granting E spell, are always available to you. Alternating between casting R and E every 1.5 seconds, after you gain that tasty Sapphire buff, keeps you safe from harm while your flock of lethal Vipers grows in size. Oh, and speaking of "growing in size," don't forget to cast W immediately after summoning each pet - you have Buzuki's Finger, whose buff duration conveniently exceeds the maximum life duration of a single Viper, so once a fresh Viper has received the buff, you'll never have to worry about re-applying it!
Each of your little green buddies can phase through walls, which is fucking sweet, and when one makes contact with any enemy units, it attacks 10 times per second, its attacks have a gigantic splash radius, and they deal 5 instances of heavy damage with every strike - one Normal Physical instance from the pet's autoattack, then one each of Poison Physical and Magical and Pure damage from the T5-A Glyph's effect, and finally the Pure Ice/Demon laser blast from Buzuki's Finger. That first instance of damage actually uses the Viper pet's Armor Pierce stat instead of Venomort's, which is nice because of his colossal stat boost from R2, but of course the real prize is being able to deal all three damage types at once, ensuring that no target can resist your onslaught.
As an added bonus, the Amethyst gem in your Cimmerian Priesthood helm will cause Fear in a large radius around you every time you summon a Viper, and your Armor of the Secret Temple also throws up another fresh set of 7 shield stacks at the same time, giving you and your friends even more breathing room than you already had! Bosses aren't immune to it, and you're free to keep refreshing the Fear duration forever!
Observe that, unusually for an RPC build, this particular Venomort needs no attribute rolls on gear, preferring instead to pick up Base Ability Damage% or Item Damage% in most slots, and optionally Armor Pierce on his gloves, if available. This is because Venomort himself is invisible, safe and happy far away from the combat zone, while his cloud of Vipers disintegrates enemies; whatever Armor Pierce they gain from Venomort will be heavily boosted by R2, allowing their Physical damage instances to more quickly punch through Spell Immune targets, which will not be affected by R1 at all... but Spell Immunity DOES NOT block the massive Pure nukes coming from Buzuki's Finger, so Armor Pierce is almost never necessary unless you're specifically hunting enemies who are somehow immune to everything except Physical damage. The only potentially threatening enemy fitting that description is the Ancient God boss in Tanari Jungle, but even if he spawned as a Paragon, your Viper cloud shreds him so quickly that he doesn't have time to complete an autoattack animation because he's too busy changing forms due to health loss. Nevertheless, I just want to make you aware of the Armor Pierce option on glove slots, should you ever need it.