When it comes to Avatar: The Last Airbender and The Legend of Korra, it's only natural for fans to draw comparisons. While the sequel series did an admirable job of striving to differentiate itself from its predecessor, there are various areas of stunning symmetry between the two. Everything from the plot to the setting to the characters have quite a lot in common. In fact, it turns out that some of the characters may have more in common than you think.
While there are universal archetypes that most genre fiction are bound to fall into, sometimes the comparison between two characters is too eerily close to be a coincidence. Case in point: Mako and Katara share a lot more in common than they might seem, and once their similarities start stacking up they almost seem like the same character.
Avatar Love
Perhaps the most straightforward comparison between the two characters was their romantic interest in the Avatar of their respective series. Whereas Katara took a while to discover her feelings for Aang, Mako and Katara hit things off with an attraction that quickly sparked into romance.
Korra and Mako's relationship fizzling out in Book Two is perhaps the most stark difference between the two romances. When Korra discovered her romantic feelings for Asami, it became clearer than ever that she and Mako were just not meant to be as a couple like Katara and Aang were. Mako and Korra ending up together certainly would have been the more expected and conventional route however wrong for each other the two characters were, and given Mako and Katara's many similarities it was probably best to diverge somewhere.
Goofy Brothers
Integral to understanding both Mako and Katara is understanding their relationships with their brothers. Mako learned to take on a more mature role as a caretaker early on when he and his brother Bolin were orphaned. While living on the streets they had to take up with sordid gangs and petty theft in order to get by, and Mako's position as the more serious and focused of the brothers sprung out of those origins. While Katara and her brother Sokka were not orphaned, the early death of their mother and their father's absence after leaving for war put them in a similar position.
In their teenage years, both sibling pairs remained extremely close despite their differences. Despite both brothers' occasional goofiness involving Sokka's experiments with cactus juice or Bolin's turn as a mover star, both became valuable members of Team Avatar. Sokka developed a great strategic mind, while Bolin found a talent for the extremely rare skill of lavabending. Mako and Katara may draw criticism from some viewers for their brooding and moody personalities, but such qualities make them perfect straight men against their brothers' comic relief.
Mementos
The comparison between the two really strengthens looking at their biographical details. After losing a parent at an early age to a violent Firebender, both characters hold on to mementos of their slain parent which they treasure throughout their lives and become featured plot points in the show as they seek to reconnect with their family. That goes beyond broad details and gets down to specifics.
For Mako, it was his father's scarf, an item which he kept until he gave it to his grandmother upon their reunion in Book Three. For Katara, the item was her grandmother's betrothal necklace, passed down to Katara's mother and then Katara herself. The necklace not only zeroed Zuko on to Katara's location during his hunt for the Avatar, but became the means by which Pakku realized his mistakes and agreed to train her in waterbending.
Master Benders
You can't talk about two masters like Katara and Mako without also talking about their skills. Both Benders rose to be some of the very best in the world at their respective arts largely through self-taught methods and some instruction from older masters. Katara's training came from Pakku, and Mako's came from the gang leader Lightning Bolt Zolt. After their training, both ascended to higher heights than even the masters who taught them, and they each become some of the Avatar's most powerful companions despite rarely carrying the heft of such a reputation.
Katara showcased her power with jaw-dropping force, commanding entire waves of water and incasing her enemies in ice to incapacitate them. She also mastered waterbending's sub skills such as healing and bloodbending and proved superlative at both. Similarly, Mako mastered his element's subskills of lightning generation and redirection. He proved so adept these talents that he could do both simultaneously while sabotaging Kuvira's mech.
Almost Fiery Relationships
A source of heated debate in the Avatar fandom is the relationship between Katara and Zuko, with both serving as trusted companions to the Avatar despite starting out as enemies. While the two overcame their problems with each other and became firm friends, many fans pushed for a "Zutara" relationship and felt that the show itself built toward the pairing. With tender moments like the two relating on their tragic backstories in the Crystal Catacombs or their mission to seek Katara's vengeance, they may have come close
What most fans might not realize is that Mako nearly had his own relationship with Zuko's granddaughter. A scrapped Book Four plotline for Korra involved Mako developing a relationship with the daughter of Izumi, herself the daughter of Zuko. While Zuko's descendant Iroh II appeared early on in the series, his sister never showed up. The creators considered playing up the Fire Nation's role in the last season more heavily, but alas, the subplot never cropped up. Just like Zutara, it's left to the realm of fanfiction for the time being.