Because he became a Kaiju for 15 minutes of fame on top of the world (lol), The Ape, the Myth, the Legend, Rah (or Karas in the English Dub) get his place in this roster.. I will put more info on this over time for anything I had (CERTAINLY) forgotten.

Rah was the Loyal Assistant and right hand Gorilla of Dr. Gori – also from the peaceful Planet of E and Soldier in the Army, it was Ra who helped Gori escape when the latter was sentence for reprogramming (the society not believing in the Death Penalty). The two would steal a spaceship and fly for years until reaching Earth with the goal of conquering it, his master deeming the Planet a jewel, infected by the decease of Humanity and through the run of the series, Rah goes to the field with every experiment created by Gori to destroy humanity, with a Kaju to boot.

Rah is the general archetype of the Mad Scientist Henchman: the big and strong comic relief lackey, prone to rage and impatience, not smart but always - despite been berated by his master from time to time for his shenanigans and deviancy from the plan - was loyal to a fault, and always willing to please him. While he would get a bit tired of Gori mistreating him he never betrayed Gori and only two times has Rah served another master, though not by his own will – one time possess by alien Zuno, and in another he was killed by a new alien ally of Gori, to show him his revival serum, serving under him, albeit briefly and return to Gori eventually. Rah was also very proud, this was shown when Gori took a normal ape and transformed him into a new servant, naming him Karas 2 who was briefly with them in Eps 5 and 6 (Due note I'm going with the English dubbed here, as I had not found the Japanese version – so I dunno if he was called Rah-2 or given any other name in the original dub).

His only abilities were Strength - and insanely strong he was, as Rah was able to smack a car off a cliff in Ep.3, killing the couple inside - and was a true master of disguises, which allowed him to operate in the field, even when he did not cover his face at times – which tells you the level of intelligence of the human up until he is in front of him – though these disguises became more elaborate and able to change his voice to suit his role.

He also had enhance sight; as seen in Episode 21, when it saw Alien Zuno through its Human disguise.

A very particular funny gag with Karas was that he would often do the same pantomime gestures with the hands as Gori did when he spoke.

Much like Gori, Rah shows nothing but disdain for any human he encountered and harm them with glee, though to an extent; he was attracted to beautiful woman to the point he kidnapped Rita, endangering Gori's operation, and was fond of Food and Drinks in one of his excursions. Rah also has the distinct honor to be among the few Monsters to face and survive Spectreman in Ep.5., continuing to serve him till the end of the show, been the fourth in the line.

By the end of the series, with his final monster beaten, Rah - who by now knew Joji/George was Spectreman - in a show of devotion to his master that even impress Gori, is enhance with information from a fighter into his body to face Spectreman. In the end though, Rah was still kill in his final confrontation with the Cyborg for good and this affected Gori more than any defeat, by now too demoralize to continue on, having lost his only friend in the whole en devour, leading to his own death.