In the Marvel Comics universe, Ikaris is a member of the Eternals, an ancient race of super-powered beings created by the Celestials. He possesses the power of flight, super strength, and the ability to manipulate cosmic energy.

In the 1991 limited series “The Eternals,” written by Walt Simonson, Ikaris flies into the sun to stop a machine called the Horde from destroying the Earth. The Horde was created by the Deviants, the Eternals’ longtime enemies, to destroy all life on Earth.
Ikaris had previously fought against the Horde but was unable to destroy it. He then decides to take drastic action and flies into the sun, using his cosmic energy powers to create a massive explosion that destroys the Horde and saves the Earth. However, Ikaris does not survive the explosion and is presumed dead.
The decision to have Ikaris sacrifice himself in this manner was likely made to add a sense of drama and urgency to the story. It also highlights the character’s bravery and selflessness, as he was willing to give his life to protect the Earth and its inhabitants.
Additionally, Ikaris’ sacrifice could be seen as a metaphor for the theme of self-sacrifice that is common in many superhero stories. Superheroes are often depicted as putting themselves in harm’s way to protect others and save the world, even if it means sacrificing their own lives.
It’s worth noting that in the current Marvel Comics continuity, Ikaris is still alive and has not flown into the sun. The character has been involved in various storylines and has continued to be a prominent member of the Eternals.
In the upcoming Marvel Cinematic Universe film “Eternals,” which is set to be released in 2021, Ikaris is played by actor Richard Madden. It remains to be seen how closely the film will follow the comics, but it is unlikely that Ikaris will meet the same fate as he did in “The Eternals” limited series.
In conclusion, Ikaris flew into the sun to stop the Horde from destroying the Earth and sacrificed himself in the process. The decision to have him make this sacrifice was likely made to add drama to the story and highlight the character’s bravery and selflessness. While Ikaris’ sacrifice was a significant moment in the comics, it is unlikely to be repeated in the upcoming “Eternals” film.