Sonic Themes

Several conflicts are repeated in the Sonic series.

Nature vs Technology

This was found in the very beginning. Here is Ivo Robotnik, a human, sticking animals into robots and building all kinds of crazy creations to take over. CD's bad futures show the extent of the pollution and corruption. 

Good vs Evil

A simple element, Sonic is clearly good and Robotnik is evil. Knuckles was the first rival, and the first to blur the lines, but it would be "neutral" characters like Rouge and Shadow that really caused questions. 

Ultimately, though, there is often a "greater" evil such as Perfect Chaos or Solaris that causes even Eggman to put aside his hatred to help.   

Light vs Dark

This is similar to the last but slightly different. In Unleashed, Chip is the light and he is good. Dark Gaia is of course the dark, and is bad. However in 06 Iblis is the "light" half, but the fire creature is a menace. Solaris itself has been a villain yet the "true" Solaris is supposed to be good. 

For the main characters it's a matter of sides. Team Dark doesn't like to advertise themselves as heroes like...Team Hero. Or any of the other teams. But they aren't evil; they aren't the bad guys. 

This is also seen with the Chao.   

Calculating vs Blind Evil

Some monsters ares simply that. They only try to destroy because it's all they know. Other villains are far more aware and planning. 

Gift vs Curse

Many characters have abnormal powers or origins that affect them. Blaze the Cat originally regarded her powers as a curse, though she used them to protect her world. Tails was bullied over his tails, but they gave him flight. 

Clever vs Naive

Many characters have been tricked at one time or another. Clever characters like Metal Sonic, Mephiles, Eggman, or even Rouge manipulate characters like Knuckles or Silver because they have a trusting nature. Sometimes even "clever" characters fall victim to someone else's plan, like Eggman to his grandfather's.