In the comics, Klaus is not immortal. He may have certain powers and abilities, but there are limitations and factors that can pose a threat to his existence.
In some comic versions, Klaus is indeed depicted as gay, with storylines exploring his romantic relationships with same-sex characters. However, this can vary depending on the creative team and the direction of the story.
Klaus isn't gay in the comic. The creators have not developed his character along those lines. The focus of his portrayal lies elsewhere in the narrative.
Klaus is not based on real events. It's a work of imagination that brings together various fictional characters and plotlines to form an enchanting narrative.
To be honest, it's not straightforward to say if Klaus is gay in the comics. It could depend on how you read between the lines or the subtext, but there's no clear-cut indication.
One aspect to consider in Finn Mikaelson x OC fanfiction is the character development. Finn has a complex backstory in the 'The Originals' universe, and when paired with an original character (OC), new dynamics can be explored. For example, the OC could be a witch who helps Finn deal with his family's issues in a different way than we've seen in the show. The relationship between them might start as an alliance against a common enemy and gradually develop into something more romantic.
There could be a fanfic where Hermione babysits Hope in a world where the wizarding world and the world of the Mikaelsons collide. Hermione has to deal with not only Hope's supernatural powers but also the cultural differences between her own magical upbringing and that of the Mikaelsons. For example, she might be confused by some of the vampiric or werewolf traditions that are part of Hope's family background. But in the end, she forms a strong bond with Hope through her patience and intelligence.
Klaus is purely fictional. It doesn't draw from any true incidents. The characters, settings, and events were all dreamed up to create a wonderful animated story that can transport viewers to a fantastical world.