For those who don’t know, invoker is a character in game called Dota 2, and playing this hero is like pushing mental processing and mechanical execution to their limits, regardless of how veteran you are in gaming, once you give it a try, the information overload is real and actual experience matters here.

Let me start with the cold, hard data that makes Invoker unique among MOBAs. Each spell requires exactly 4 keystrokes minimum - three orb combinations (Q/W/E) plus the Invoke key (X). With 10 available spells, that’s 40 keystrokes just to cast every spell once. But here’s where it gets interesting: in actual gameplay, you’re not casting spells in isolation and obviously not random.

To mathematically express how Invoker spells are computed here: $$ \text{Number of combinations} = \binom{n + r - 1}{r} $$

Where:

\begin{flalign} \text{n = 3 } (\text{types of orbs: Q, W, E})&& \end{flalign}

\begin{flalign} \text{r = 3 } (\text{3 orbs per spell})&& \end{flalign}

$$ \binom{3 + 3 - 1}{3} = \binom{5}{3} = 10 $$

For starters, it requires understanding of game and the hero itself, and obviously being comfortable with the execution, like pressing keys in keyboard as quickly as possible. And beyond raw mechanical execution, Invoker presents a unique challenges, where we talking about:

• Spell patterns
• Spell cooldowns
• Spell usage (when to use what)
• Resource optimization
• Positional awareness

Obviously I am no expert so far yet, hence, I am planning to document it here and might update it sooner how it goes, meanwhile, here is a small gist of how it goes in this video