Leonardo, or Leo to his friends, had many large obstacles that he had to overcome.
Firstly, he was born a turtle. This made it difficult to deal with humans, and I am sure learning to speak properly using a reptile's mouth, tongue, and vocal chords made it more so. Also, being a 6 foot tall turtle probably made him shunned by people until they got to know him better.
His home was a sewer, albeit it was fixed up, but one can never really get rid of the smell fully.
He was made a leader even though he didn't ask for it. This can be tough, especially in his early teenage years, where he had to deal with added responsibility. He questioned himself a lot during this time period, and it was quite wrong to thrust so much responsibility on a kid like that.
And lastly, though he carried two swords, he never seemed to be able to kill anyone. Not sure about you, but this to me is a huge obstacle. It's like having a gun but no bullets.
