Donatello

Donatello is still the smartest turtle like all of his incarnations. Like the other turtles except for Raphael, he loves the future for its new technology and gadgets.

Personality
Like in the Mirage comics, Donatello has a complex personality in the 2003 animation and thus is a popular character. Several episodes concentrate on him, as well as his emotional and intellectual struggles.

As in his other incarnations, Donatello is knowledgeable, a skilled technician and tinkerer, and very introspective, frequently becoming pensive over things he doesn't understand. He typically has a very close, however platonic, relationship with April. He also displays closeness with Michelangelo akin to that, seen in the original movie. Even more pacifistic than his other incarnations, Donatello shows a greater interest in technology than his ninjutsu training. During his first Battle Nexus Tournament, despite being a very gifted ninja, he lost in the first round of the competition. Even so, Donatello will defend his brothers at any cost, and he frequently assists the team in many ways through the technology he develops, mostly vehicles and communication devices. Much like Leonardo, Donatello does his best to prepare for any situation which is emphasized during the turtles infiltration of the Shredder's tower where Don carried all the equipment and gadgets they would need.

In this series' incarnation, Donatello is generally well-liked by all of his brothers, never engaging in major confrontations with them. In fact, Donatello was the one to reunite his brothers against the Utrom Shredder in the episode Same As It Never Was. His skin color is an olive green color; this particular color is only used for him in the 2003 animation. In the fourth season, he was infected by a monster, and in the episode Adventures in Turtle-Sitting, he mutates into a monster himself (which happened to Raphael in the Mirage Comics).

Leatherhead considers Don to be one of the most gentle-natured people he's ever met. When he mutates into a monster, he loses his gentle personality and becomes violent and aggressive. However he does show signs of calming down whenever Master Splinter talks to him and is eventually returned to normal thanks to Baxter Stockman's cure.

Trivia

 * Like his brothers, Donatello is a practitioner of Qi Gong, as shown in Turtles in Space, Part 3: The Big House.
 * He is right-handed.