Donatello

Donatello is Splinter's third adopted son and Karai's adoptive brother, but he is the biological brother of Leonardo, Raphael, and Michelangelo. Donnie is a scientist, mechanic, and inventor, responsible for the design and manufacture of all the tools, gadgets, armor, vehicles, and weapons in the Turtles' arsenal, as well as a talented hacker.

Wearing a purple headband, he fights with a Bo staff that also transforms into a naginata (Japanese halberd) using the blade at one end of the wooden staff.