Michelangelo

Michelangelo is youngest son. His trademark nunchaku  are once again his primary weapons, but he has used other weapons such as grappling hooks and those of his brothers.

Childhood
Michelangelo was a pet turtle bought by a young boy along with three others, Donatello, Raphael and Leonardo. The boy was waiting at the crosswalk when a teenager noticed a blind old man crossing the street while a truck sped toward him. The teenager bumped into the boy with the turtles, causing him to drop the bowl in which he held them. The turtles fell into the sewer. Meanwhile, the teenager had successfully saved the old man's life, and while the truck veered away from the scene, the doors flew open and a canister fell right into the sewer with the turtles, covering them with an odd substance. A rat by the name of Splinter was passing by and picked up the turtles, touching the odd chemical as well. When Splinter woke up one morning some point later, he found he and the turtles had grown taller, and slightly more intelligent.

Splinter thought it wise to train them in ninjutsu, just as his Master Yoshi had unknowingly done for him. Michelangelo and his brothers were taken by Splinter to Japan when they were children to bury Hamato Yoshi's ashes with Tang Shen's remains, and alerted the Ancient One of his and Yoshi's condition. The turtles constantly noticed an odd demon visible to them, but invisible to the Ancient One and Splinter. Finally, when the Ancient One went to consult with the Ninja Tribunal, Splinter noticed an odd smell in the air, believing it to belong to the demon the turtles continued to see, and they secretly followed the Ancient One. The two ninja masters finally were attacked by the demon, but Leonardo managed to throw a stone at the amulet, causing it to shatter and reveal the demon. The Ancient One and Splinter quickly killed the demon. The Ninja Tribunal applauded the turtles' efforts, though eradicated all memories of the trip. The Ancient One gave the turtles bandanas, Michelangelo's being orange. The Tribunal used their connection with nature to wrinkle space and open a portal to the turtles' current lair.

Personality
Michelangelo is slightly more immature than in the 1987 series and likes to tease and annoy his older brothers, especially Raphael, to whom Michelangelo is the foil. In fact, a running gag is that whenever Michelangelo says or does something excessively outrageous, usually involving a catch-phrase from the 1987 show, one of his brothers (usually Raphael) will slap him on the head. Other characters such as Master Splinter and the Ancient One have picked up on this habit, but usually, use it only whenever he disobeys.

Raphael and Michelangelo mostly have a love-hate relationship in which Michelangelo frequently antagonizes Raphael, but Raphael shows that he cares about him whenever he's in danger. He also seems to be very close to Donatello.

Michelangelo is regularly treated as the youngest brother and little is expected of him, although he has proved to have exceptional speed and agility. He has shown empathy for others, as proved in particular by his adoption of Klunk, a stray kitten and his friendship with Leatherhead.

In some episodes, Michelangelo takes on the role of a costumed super hero called "Turtle Titan." While having no superpowers and gadgets, he proves himself quite effective in his own right and even befriends other superheroes, such as the Silver Sentry and the Justice Force. As Turtle Titan, Michelangelo uses grappling hooks as both a weapon and a mode of transportation, and a small shield used for protection and as a throwing weapon.

Although not shown as particularly focused on ninjutsu, preferring to spend his time reading comics or watching movies, Michelangelo is quite an effective fighter. In the Season 2 finale "The Big Brawl," he became the Battle Nexus Champion, the best fighter in the multiverse. Although his victory was due in part to some very lucky breaks, Michelangelo later won a rematch against the last finalist and earned a medal of honor for his behavior during the battle. In some episodes - particularly Return of the Justice Force, Touch and Go, Reality Check, Membership Drive and The Unconvincing Turtle Titan -, Mikey even demonstrates quick wits and intelligence, aiding his allies and brothers with decisive ideas. While this proves he is actually more intelligent than he lets on, it is implied that he has very little interest in seriously focusing his intellectual development.

In early profiles of the 2003 animated series, Michelangelo is regarded as being the most athletic of the four, although unfocused on training mentally (though those are admittedly old profiles and may have been early plans for the character, he has certainly proven he is an effective fighter when need be). This profile statement has since been repeated in the profile of Michelangelo in the lead-up to the debut of the Fast Forward season, which began airing on July 29, 2006.

Ninja Tribunal
Michelangelo became one of the Ninja Tribunal's Acolytes along with his brothers. It should be noted that although Michelangelo tends to goof off, his spiritual avatar is that of a dragon along with his brothers as seen in the episode. It was seen that he was advanced when it came to the stealth training with Hisomi.

When Mikey was a kid, he and his brothers went with Master Splinter to Japan to bury Master Yoshi's ashes next to his beloved. While there, they helped Master Splinter and the Ancient One win a fight against a demon and that was when they gained their ninja masks.

Fast Forward
In this series, Michelangelo, along with his brothers, traveled into the year 2105 and met the great-grandson of April and Casey, Cody Jones. Mikey continued his videogaming in the future, completely awestruck by the new video games, especially since most of the games were virtual reality pieces. When the Turtles and Master Splinter reached the future, they were provided with tech-upgraded weapons, courtesy of O' Neil Tech (which Cody owns). Michelangelo first chose a giant power armor suit, which kept Mikey happy for five seconds before he found out that it was too cumbersome for him to operate; so he returned to his (though upgraded) nunchaku standards.

Overall, Michelangelo continued being the obnoxiously annoying little brother. He kept his addiction for video games and it even increased and he became even more obsessed with them, which proved to be a hazard during Graduation Day: Class of 2105which almost got him to not graduate as he missed a month's worth of training just for playing video games. He made up for it, however, when he passed the three tests to graduate and got back his nunchucks: Invisibility (where the first handle bar was guarded by Leonardo), Strength (where the second handle bar was guarded by Rapahel), and Insight (where the chain was guarded by Donatello). He also passed the hidden test of humility after admitting that he did not deserve to graduate just because he passed three tests after missing so much training.

Back to the Sewer
In this series, Mikey continues to be obnoxious and pestering as he always has been in the 2003 series. Mikey was sad to leave behind all of his stuff in the future, including his video games and weapons. Michelangelo still loves his video gaming, and this becomes an important factor in the episode 'SuperQuest' where the turtles must enter one of Mikey's video games to collect more of Master Splinter's data bits that were lost in the beginning of the series. In "City Under Siege", Mikey defeats the Cyber Shredder by destroying the platform they were on and burning Shredder to a crisp. Mikey also goes to Casey and April's wedding at the end of the series where he battles Foot ninjas and helps beat the Cyber Shredder. Afterwards he sees Casey and April getting married. By this point he seems to have matured a little bit.