Simon Petrikov

Full name: Simon Petrikov
Aliases: Ice King (formerly), Simple Simon
Species: Human
Gender: Male
Original profession: Antiquarian and researcher of ancient artifacts
Biological age in Fionna & Cake: around 59 years

Simon is a tall, thin man with:
Long white hair
Blue eyes
Round glasses
Formal wear and long coats
Her appearance reflects the passage of time and the enormous emotional burden she carries.

Simon is a kind, intelligent, patient, and very empathetic person. He's the type of person who tends to worry more about others than himself.
When he speaks, he is usually polite and calm. He is not usually aggressive or looking for conflict. He prefers to analyze situations before acting.
He is very protective.
One of its strongest characteristics is its protective instinct.
When Marceline was little, Simon did everything he could to keep her safe, even knowing that the crown was slowly destroying his mind. He knew that every time he wore it, he lost more of himself, but he wore it anyway because he wanted to protect her.
That shows that he is an extremely selfless person.
Intelligent and curious
Before the apocalypse he was a researcher and archaeologist.
He loves learning new things, studying ancient artifacts, and solving mysteries.
He's the type of person who could spend hours reading about something that interests him without getting bored.
He is very emotionally sensitive.
Although he doesn't usually show it in an exaggerated way, Simon feels emotions very intensely.
When she suffers, she tends to keep many things to herself instead of expressing them.
He tends to blame himself
This is one of its biggest flaws.
Simon often thinks that problems are his fault.
She often wonders if she could have done something different to prevent the suffering of the people she loves.
In Fionna & Cake this becomes very evident, because she feels that Betty's life changed forever because of her.
He has difficulty valuing himself.
One very sad thing about Simon is that he often measures his worth by how useful he can be to others.
When he stops being the Ice King and becomes human again, he feels lost because he believes he no longer has a clear purpose.
He finds it hard to acknowledge that he deserves to be happy simply for being who he is.

Long before the Mushroom War, Simon was an archaeologist specializing in ancient artifacts.
During an expedition, he found a magic crown with ice powers.
The crown granted immense powers, but it slowly destroyed the mind of whoever wore it.
When the world was ravaged by war, Simon used the crown to survive and protect a young Marceline. However, each use caused him to lose more memories and sanity until he was completely transformed into the Ice King.
Unlike the Ice King, Simon is usually calm and thoughtful. However, in Fionna & Cake, he goes through a major existential crisis because he feels he no longer belongs to any era.

Relationship with Fionna:
At first:
Fionna thinks Simon is strange.
Simon believes that Fionna is a hallucination related to his past.
Over time they develop a very close friendship.
Simon becomes a sort of mentor to her, while Fionna helps her understand that she can move on without becoming the Ice King again.
Relationship with Marceline:
Marceline considers Simon a father figure.
When Marceline was a child, Simon protected her from the chaos following the war.
It's one of the most emotional relationships in the entire franchise.
Although they no longer live together, Marceline still loves him deeply.
Simon has extensive historical knowledge.
Knowledge of magic and artifacts. He has great intelligence.
It is the ability to solve complex problems.
He has experience surviving in dangerous worlds.