Fic series centered around Hun that is also pulling in the other turtles into it.
first story The Protector
http://www.fanfiction.net/s/5605906/1/The_Protector
second story The Jewel
http://www.fanfiction.net/s/5654278/1/The_Jewel
and the third in progress Shadowplay
http://www.fanfiction.net/s/5760706/1/Shadowplay