There is no legitimate "one-hit kill" cheat in Dota 2.
Why It's Impossible
Server-Side Authority: All combat math (damage, armor, HP, regen) executes on Valve's servers. The client cannot override "SetHealth(0)."
VAC / Overwatch / Vanguard: Kernel-level anti-cheat (Vanguard in some regions) detects memory injection, DLL hooks, and packet manipulation. Bans are permanent and hardware-ID linked.
No Public Exploit: Historical bugs (e.g., old Techies mine stacking, pre-nerf Ursa Fury Swipes) were balance issues, not cheats, and were hotfixed.
What Players Mistake for a Cheat
One-Shot Combos: Lina (Laguna Blade + Aghanim's + Veil + Ethereal), Skywrath (Mystic Flare + Concussive Shot + Ancient Seal), Lion (Finger of Death + Aghanim's + Veil). These are intended mechanics.
Visual Desync: High ping or particle lag can make damage appear instant.