131 Hadoo

At first, I figured Hadoo to be a parody of Goku from Dragon Ball Z.  Goku is the main character of this franchise and has been named the #1 anime character of all time.

Then I realized that he might be a parody of Ryu, the main character from the Street Fighter series of video games.  The two characters are similar and often compared to one another anyway.

The TDD figure is probably an intentional mix of both.  Hadoo has Goku's hair, but Ryu's attire. 

But there is more...

Hadoo has a zood named Ken.  He is a little fire flame with a face. You might call him a flame imp or a fire elemental.  I figured that he was named Ken as a play on the name of the famous filmmaker Ken Burns. Get it? The TDD designers love these little puns.

Then, I learned that Ryu's best friend is named Ken. This character can send bursts of fire from his fists as part of his fighting style. Guess what this "fireball" is called in Street Fighter: The Hadoken!

Hadoo + Ken = Hadoken

In fact, there are quite a number of moves in Street Fighter that have the term "Hado" or "Hadou" in their name.

So this is my final answer: Hadoo is a parody of Ryu from Street Fighter!