Knuckles is an enthusiastic fighter who can knock down his opponents with only a single hit. Keep punching opponents to defeat them quickly!

Knuckles the Echidna (ナックルズ・ザ・エキドゥナ Nakkurusu za Ekiduna) is a protagonist in Sonic Battle. He is an anthropomorphic 16-year-old red echidna and the current guardian of the Master Emerald, a powerful ancient relic which is his solemn duty to protect from anyone who wants to abuse it. His dominant traits are his superhuman strength, and the two spike-like knuckles on each of his hands, from which his name is derived from, which he can use to dig with and climb up walls with ease. He can also trap the wind under his dreadlocks to glide through the air.

In Sonic Battle

In Sonic Battle, Knuckles heard from the news that an E-121 Phi had been robbing jewelry stores. Later, Knuckles met Sonic and Tails and Emerl, a Gizoid Sonic had found, who had come to ask for the Chaos Emerald in his possession to develop Emerl. Knuckles, however, mistook Emerl for the E-121 Phi and attacked him, but was defeated. Knuckles then relinquished his Chaos Emerald and heard about Emerl's abilities and that Eggman and Rouge were after him, making him suspicious.

Later, Knuckles met Tails and Emerl, where he, after a brief fight with Emerl, was then told by Tails to come to Emerald Beach when their path was blocked by Chaos Gamma. In the end, Knuckles took care of Gamma alone, allowing Tails and Emerl to leave. When Chaos Gamma escaped, Knuckles got to Emerald Beach, where he saw Rouge leave and heard what had happen from Sonic. When Knuckles tried to ask Emerl, he became infuriated as Emerl continued to ignore him, especially upon Sonic's orders, which made Knuckles fight both of them.

Later, after Emerl had been stolen by Rouge, Knuckles and Tails aided Sonic when he fought Rouge to get Emerl back, with Rouge eventually surrendering Emerl. Later on, when Knuckles learned about how Emerl needed Chaos Emeralds and that he grew stronger the more he fought, he vowed to help realize his full potential. Finding Emerl with Tails in Emerald Town, Knuckles trained with him until they heard the news saying that an E-121 Phi in Night Babylon, and Knuckles took Emerl with him to deal with it.

In Central City, Knuckles briefly came across Amy, only to be attacked by Chaos Gamma. After forcing Chaos Gamma to leave, Knuckles encountered Rouge, who filled him in on Chaos Gamma and learned the robot wanted revenge at Emerl. After processing this, Knuckles and Emerl continued to Night Babylon. There, they met a clerk who mistook Emerl for a Phi and called a Guard Robo. After destroying it and escaping, Knuckles lost his temper and yelled at Emerl and upset him. Apologizing for his outburst, Knuckles had Emerl wait while he went ahead. When Knuckles returned, however, Emerl was gone and he began looking for him. After several kermises with store clerks, Knuckles found Emerl with Rouge. Knuckles thought Rouge was after Emerl, but he found her innocent. Just then, they found the Phis. Knuckles and Emerl proceeded to destroy them and got their Emerald Shards before being given a Emerald Shard from Rouge as well who suggested they asked Tails about the Emerald Shards.

Heeding Rouge's advice, Knuckles returned to Tails who explained they could get a whole Chaos Emerald if the collected two more shards from the Phis. Knuckles then left with Emerl to train him and fought him to settle their score. After their battle, Dr. Eggman appeared and attacked them with a Phi, but Knuckles and Emerl defeated it, claimed its Emerald Shard and chased Eggman. Finding Eggman in Central City, Knuckles and Emerl destroyed another Phi and took its Emerald Shard. There, Knuckles acknowledged Emerl as his battle partner, before hearing Eggman say that he was heading to Gimme Shelter as he escaped.

As Knuckles got at the Gimme Shelter to catch Eggman, he was caught in Eggman's "spiky rodent trap" and Eggman revealed he tricked him. As Eggman announced plan to have Emerl absorb his Final Egg Blaster, Knuckles was left in Chaos Gamma's hands, but Emerl defeated it. Afterward, Knuckles asked Emerl to free him, but Emerl scoffed him for his lack of strength, infuriating him enough to try and break free, until Emerl shut the trap down. Heading back to Emerald Town, Knuckles had Tails put their Emerald Shards to a whole Chaos Emerald, which they gave to Emerl. As Tails wondered what happened, Knuckles asked Emerl to keep it a secret that he got tricked by Eggman. Regardless, Emerl still told Sonic and Tails, making Knuckles explode with anger.

Later on, Knuckles met Emerl again, who had come to fight him so he could fight Shadow, where he was still defeated. Later, when Eggman revealed his newest Death Egg and its Final Egg Blaster, Knuckles met up with Sonic, Tails and Emerl at Holy Summit, where he revealed that Chaos had returned, a sign of danger. As Emerl went to the Death Egg to stop Eggman, Knuckles and the others watched Emerl through a monitor.

When Eggman was defeated, however, Eggman fired the Final Egg Blaster, destroying some stars, causing Emerl to revert to his original destructive programming. However, Eggman could not control Emerl as excepted, and Emerl prepared to fire the Final Egg Blaster at earth. Knuckles then urged Sonic on as he went to the Death Egg to stop Emerl with the Master Emerald. When that failed, Sonic had no choice but to destroy Emerl. Once the deed was done, the world was saved, but everyone mourned Emerl's death.