First Stay on Earth
In the year 1975 an Utrom expedition was launched to observe the planet Earth and its various species but a malfuction in the ship's drive caused them to crash on the planet. With most of the ship destroyed and a third of the crew dead the survivors took whatever was salvageable and used their exoskeletons fitted with false skins to disguise themselves and integrate in human society in New York.
After several years the Utroms had acquired enough money to purchase a building and began to adapt it for their needs building a device to communicate with their planet. Impressed with how well they had adapted to human life their leaders asked them to continue to overserve human society using their Techno Cosmic Research Institute as a front.
Moving what little was left of their salvage to the city a road accident caused a cannister of mutagen to fly out of the truck and shatter a child's glass bowl with four baby turtles, both vanishing into an open manhole. This would not be their only accident involving mutagen, in one of their labs a small alligator they were studying was exposed to the substance which mutated him. Calling him Leatherhead they allowed him to live with them educated him.
Fifteen years after this event two Utrom workers came upon an injured Splinter in the sewers and chose to take him back to their building to heal him. Coming investigate their connection to TCRI the Teenage Mutant Ninja Turtles saw the Utrom's true forms and were accidently teleported to another planet by their transmat machine. Eventualy managing to locate the turtles on one of the Triceraton homeworlds they teleported the turtles back with their new friend Professor Honycutt (the Fugitoid) and several Triceratons also caught in the teleportation beam. After a minor skirmish the Utroms teleported the Triceratons back to were they came from. Reuniting the turtles with their father they explained their connection to them but unfortunately at that time the giant flashes of light which was a result of the Utrom's transmat machine had attracted the attention of the police and the National Guard. Offering Honycutt a place with them the Utroms teleported themselves back to their homeworld self destructing the TCRI building behind them.
In their haste to leave Earth the Utroms had left Leatherhead behind. Years later a group of Utroms came to extract the mutant alligator. These Utroms were part of a secret religeous sect called the "Illuminated" who believed it was their god given duty to cleanse the universe of all violent species so that peaceful ones can live without fear or hindrance. They had secretly been experimenting on Leatherhead to make him the perfect weapon so now they could make an army of his clones to attack other worlds.
Learning of this, the other Utroms led by a man called Ribky enlisted the aid of the turtles for a mission to rescue Leatherhead. Breaking him out of the of the Illuminated's base on a moon Ribky stayed behind and sacrificed himself in order to destroy the base. The other Utroms explained that Ribky was in charge of waste disposal at the TCRI facilty and so was responsible for the accidents that mutated Leatherhead and the turtles. Feeling responsible for his creations he had to make sure they were they were all okay before he died.
Official First Contact With Earth
The current comics began with the Utroms and Honycutt on the moon with a giant structure hidden in the surface of the dark side. The facility soon dislodged and along with a smaller escorts made it's way towards Earth. In a very public arrival the the structure landed in the water of the Atlantic Ocean just beyond Upper New York bay.
The Utroms presented the crew of the missing shuttle Defiant. The Utrom's leader Korobon addressed the United Nation and offered to make Earth a center for interstellar trade, exchanging culture, art and technology. They promised to stay for one year and if then the governments of Earth wished for them to leave they would do so and not return for a hundred years.
In five months human society adjusted to the the knowledge of the existence of alien life with economy vastly changing, religeous groups stuggling to rationalise it, goverments rising and falling as well science books being rewritten but in the end it seemed that for the most part the presence of Utroms were accepted by society but not without prejudice by some. Also other alien vistors arrive via a transmat on the Utrom's "Moon Island".
Preferring a non lethal human security force the Utroms chose the Foot Clan to compliment their own security force at their base. The Utroms also launched exploration missions to other parts of the world such as the deep sea caribbean and Tepui were a small group of Utroms had been lost during their first sojourn on Earth. These Utroms had developed new technology to help them survive in the jungle such as Bio-Exoskeletons made of wood and Quantum Inversion Redimensioning rays which allowed them to stay hidden inside a peach pit. Accompanied by Donatello the expedition team found their lost brethen and they returned with them to their base.
The Utroms stay on Earth has not been entirely smoothe thus far as there are some humans that resent their presence with riots in parts of the city, a dangerous terrorist group called the Xihad has emerged and bombed Upper New York harbor and a member even attempted to suicide bomb Galaxies, a bar in the city catering specificaly to visting aliens.
Glurin is a young scientist that features prominently in the current volume of Teenage Mutant Ninja Turtles. Described as one of the brightest that came to Earth he has worked with Professor Honycutt on some of his theories on the transmat being used not only to move through space but through alternate dimensions and time.
He is friends with the turtles and their friends, often socialising with them at Galaxies. He first observed an alternate reality version of the turtles in which they had super powers. He also tested his theories with willing test subjects Donatallo, Raphael and Casey Jones, sending them to an alternate Earth which had been mankind had been annihilated by giant killer insects. He also attended Master Splinter's funeral.
Glyminal is one of the Utroms that was on Earth during the Utrom's first stay on the planet. while developing their transmat, it produced unwanted byproducts that they couldn't dispose of safely with limited resources thus they had to find remote places to temporarily bury it. Glyminal led a mission to do Tepui but equipment failure meant they were marooned in the jungle.
Not wanting to risk sending a message to for fear it would be intercepted by humans he and the others from his mission started to adjust to life in the jungle. Leaky mutagen cannisters had a strange affect on plants and the some lizards. This led them to developing organic-exoskeletons and later using the lizard mutants to do labor until they gained sentience and rebelled. The most important new invention was the QIR device which allowed them to shrink and live a hidden existence in a peach pit which was appropriatly reinforced.
Years later when an expedition team came to search for them, Glyminal recomended experminating the lizard mutants until Donatello convinced him to use the QIR device on them and let them live in their habitrail. Glyminal returned to New York, and teaching his brethen of some of the breakthroughs they've made. He differs in appearance to other Utroms, having spikes on his body due to him using the organic exoskeletons.
The most well known Utrom, due to his role in the classic 80's series, current IDW series, and his re-imagining as an Utrom, he is dangerous to an extreme, known as Dimension X's deadliest warlord. In past incarnations Krang has stated he was stripped of his body, and turned into his brain-like form by the Eye of Sarnath and Turnstone, this may indicate the other Utroms were likewise formerly bipeds but shared Krang's fate in the reality manipulation that altered him.