Maybe your right. Maybe I am just a weakling. But I'm perfectly fine with that. There's nothing wrong with being the weakest. I don't care if I'm the weakest Kaiju to ever be recorded in Terran history. As long as I have the courage to stand up and face those who are stronger, then that's more than enough for me as long as I can protect those I care about.
-Anguirus to Destoroyah in "Survival of the Fittest"
Anguirus is a founding and current member of the Earth Defenders and is one of Godzilla's closest friends and rivals. He was originally a normal Ankylosaurus that survived the KT Extinction and mutated over time before awakening on Iwato in 1955, becoming further mutated by atomic testing. Anguirus would later confront Godzilla in 1967 in Vietnam, becoming Godzilla's first enemy Kaiju.
Anguirus is a four-legged dinosaur-like creature that combines the features of an Ankylosaurus, Styracosaurus, and a crocodile. He has several horns at the top of his head and a single rhino-like horn above his nose.
His face is elongated with a long snout bearing rows of jagged, serrated teeth and his carapace is studded with long, sharp spikes. Anguirus' tail is longer than his body and makes up most of his body length, and is also covered with spikes. His hind limbs are longer than his forelimbs, enabling him to stand up on them to his full height, but he generally walks upon all fours.
After becoming a member of Fairy Tail, Anguirus is given his Guild Mark which is black and located on the right side of his neck.
Before he cared about protecting the humans, Anguirus, like many other kaiju, was vengeful towards humanity due to their atomic testing mutating him and destroying his home of Iwato Island. However, similar to Godzilla, Anguirus eventually learned to forgive the humans, especially when humans helped him out in his battles like in his battle with Destoroyah.
Anguirus is depicted as a very tenacious and fierce fighter. Despite constantly going up against enemies tougher than himself, Anguirus rarely backs down and always puts up a vicious fight. Despite his fierce nature and his rivalry with Godzilla, Anguirus shares a very close friendship with Godzilla now ever since he found out that Godzilla had come to aid him in his battle with Destoroyah.
He is very close with Godzilla and is usually the first one on the scene when he needs help, such as when Anguirus showed up to assist Godzilla in his battle against Mecha-King Ghidorah and two Cryog MechaGodzilla's and when he saved him from a group of Dark Unicorn mages. He also has developed a close friendship with Erza Scarlet and has even confessed to her about how he nearly died during his battle with Destoroyah and how he felt fear for the first time, showing that he is trusting enough to share his own personal feelings with others he trusts.
He is a little rough around the edges and was never especially malign, but can act very gruff at times. Still, to his allies he is steadfast and loyal. When in combat he'll very rarely give up, no matter the odds against him and is often said to have a 'Never say die' attitude. He often acts as second-in-command to the Earth Defenders alongside Godzilla.
Not much is known about Anguirus' past other than that he was an Ankylosaurus that survived the CT Extinction and was mutated over time. At some point after the KT Extinction, Anguirus became frozen in ice but managed to get free. Anguirus then settled on Iwato Island and went into a state of hibernation. On April 24, 1955, Anguirus is awakened by atomic tests performed on the islands, the radiation from the test further mutated him. Over time, radiation also began to slowly destroy Iwato, turning it baron. On May 21, 1959, Iwato Island was turned completely uninhabitable and Anguirus was forced to leave, making his way to Asia, remaining underground most of the time.
Sonic Roar: During the Tenrou Island Arc, Anguirus has displayed the ability to employ a powerful, sonic-based roar that is mostly used to disorient enemies, but is still capable of hurting other monsters and destroying military weapons. It can also destroy, and even pass through, buildings and rocks.
Anguirus Ball: Anguirus' signature attack, he curls himself into a ball and rolls into his foes. This attack is often used for him to travel at fast speeds, but is also capable of severely injuring enemies; this attack was able to defeat Gigan by striking him in the head.
Thunderball: After being exposed to Tenrou Island's Magic Power caused by Azuma's Terra Clamare, the dormant radiation inside Anguirus' body that caused his mutation became affected and allowed him to unlock this attack. He first heats up the spines on his carapace before entering his spike-ball form and charging into his opponents. This attack was shown to be able to cause incredible damage to Destoroyah after being struck by it, breaking through her armored body and knocking her out cold.
Immense Strength: Anguirus is one of the several Kaiju that doesn't posses a lot of powerful ranged attacks, so he relies more on fighting with his teeth and claws. He has also been shown to use his spiky tail in battle. During his first battle with Godzilla, before mastering his rolling attack, he was known to hurl himself backwards at a foe, ramming into them with his spiny carapace. His strength also allows him to burrow underground with relative ease.
Immense Endurance: Anguirus possesses astounding stamina and determination, able to keep fighting after absorbing vicious assaults that would normally force other monsters into retreat. Despite repeatedly facing opponents more powerful than him such as Godzilla, Gigan, Mechagodzilla, and Destoroyah, he has never retreated from a fight without first taking substantial punishment. After helping Godzilla in his battle against Mecha-King Ghidorah and the Mechagodzilla's, Godzilla was visibly exhausted, but Anguirus gave Godzilla a sarcastic glare, almost as if mocking him for being tired by the battle.
Immense Durability: Anguirus has been known to posses impressive resilience. During his battle against the Cryog's Mechagodzilla, Anguirus was brutally beaten and apparently killed by a Mechagodzilla, but after being transported to Siberia by Kiryu before it was shot down by more Mechagodzillas, he broke free from Kiryu's restraints and immediately joined forces with Godzilla to battle an army of Mechagodzillas and Mecha-King Ghidorah. During the battle, Godzilla even utilized Anguirus as a flail, grabbing him by the tail and slamming his carapace against Mecha-King Ghidorah, with Anguirus showing no visible pain.