What is the use of shadow

Shadow the Hedgehog, is a dark character that is good, but has a constant battle within himself of self control, whether to seek for power any means nessesary eventually corupting himself and turning evil. Or using the power he all ready has, to the point where he can use a little amount of effort to achieve a big result.

He is a unique example to watch, observe, and learn from.

Like Sauske from Naruto, or Shoun from Bakugan, or Inuyasha, or Ichigo from Bleach.

They all have a dark past, and they overcame that darkness and they became more powerful than they were before.

That is why Shadow is useful, he represents people that go through terrible times, and make it by becoming stronger in the long run.