Agents of SHIELD season 6 villain, Izel, isn't inspired directly by the comics, but the character does still possess roots within the Marvel source material. First introducing herself to Fitz and Simmons as a supposedly friendly face, Izel offered the two stranded travelers passage back to Earth, for which the couple were sorely grateful. It didn't take long, however, for suspicions to be aroused and it transpired that the harmless artifacts Izel was seeking on Earth were actually the diabolical monoliths that have plagued the Agents of SHIELD team for the past few seasons.
Izel is eventually revealed to hail from a Fear Dimension, where life forms are unable to experience sensation or take proper form. Clearly one of the more powerful and ancient among her kind, Izel's key ability is to possess other life forms using sound vibration and she is also able to influence the minds of Fitz's shipmates without much effort. Izel does this by creating and controlling Bat-like creatures called the Shrike, and her main aim in Agents of SHIELD season 6 is to open a doorway to her own world and let her people possess the inhabitants of the prime universe.
There is no obvious, direct counterpart to Izel in the Marvel comic books, but like most of the original creations in Agents of SHIELD, certain roots can be found within the source material. The name Izel is derived from the name Ixchel, and a figure by this moniker does exist within Marvel canon. However, a title isn't the only thing Izel and Ixchel share. In the comics, Ixchel is a Mayan God who is present when the Celestials hold the Third Host, a test of Earth's progression. They approach the Gods of Earth and promise to return in 1000 years to judge the planet's right to exist. While many of the Gods prepare to fight back against the Celestials, a group of Goddesses, including Ixchel, opt for a more peaceful solution and seek out Earthlings that are virtuous enough to prove the race worthy.
While this is quite different from Izel's origin story, there are several points of crossover that mean the connection is unlikely to be a coincidence. Izel arrived on Earth from her own dimension and was immediately hailed as a deity by the Incan (rather than Mayan) civilization, who mistook her abilities as signs of God status. In the Marvel comics, Gods are also beings from other worlds that humans interpret incorrectly, and the Celestials refer to this during their declaration. Just like Izel, therefore, Ixchel came to Earth from another realm and was made into an idol, albeit in a different part of the American continent.
There's a clear difference between Izel and Ixchel in terms of alignment, with the latter an ally of mankind, and Izel a remorseless invader with no love for humanity. However, their similar names, links to ancient Central and South American mythology and other-worldy origins can't be ignored, and it's possible that Ixchel formed a base template for Izel in Agents of SHIELD season 6. This is a neat way of bringing fresh characters into a TV series, but ensuring the link back to the original Marvel stories isn't completely lost.
Agents of SHIELD season 7 will premiere in 2020 on ABC.