Meant mostly for Flan, rambling speculation under the cut.

So as you said, the crown is obviously malicious in some way, with a possible goal of covering the world with ice. However, it is also controlled by its wearer to a certain extent, and their madness is not entirely inflicted but rather originates from their own personalities.

Which, as you said, implies that Simon Petrikov/The Ice King has MAD self control liek woah. Finn went nuts SECONDS after putting it on. Petrikov, the mild-mannered antiquarian, took what looked like years. We see him not wearing it at times too, so we know he was aware that it had One Ring-like corruptive capabilities.

However, he also states its keeping him alive. Marceline may have survived the apocalyptic Mushroom War and its fallout because she’s half-demon. That would imply that he knew he wouldn’t survive it as a normal human, and going through a kind of “detox” to rid himself of its influence would leave him defenseless. That, or he really was dying for other reasons too (possibly age, illness or radiation? we don’t know how long he was wandering out there before he met Marceline).

So while still relatively sane, Simon clearly knew that the crown made him crazy. As you said, in his fanfic where Fionna knocks the crown away from Cake otherwise she’ll “get the Ice Queen’s crazy” may just be the script, and the Ice King’s fanfic is just a framing device. BUT, notice that the happy ending INCLUDES the destruction of the crown? A happy ending the Ice King wrote? If we’re in the process of over-analyzing cartoons, then that has got to count for something.

I would therefore say he’s got a bit of a Gollum thing going on, where he knows it keeps him alive, but it also obsesses him and drives him crazy. Getting rid of it would be a blessing, but its not something he’s capable of doing on his own. There might not even be a point anymore, his memories as Simon may already be gone, except for hints that come out subconsciously like his need to follow Marceline around. (*sob*) As an aside, I can’t wait for the episode Simon & Marcy I CAN’T.

BUT BACK TO FINN - So it orders him to cover the world in ice, and preys on his heroic instincts, not to mention the madness and rage of the moment, to basically make him go bonkers instantly. It also talks to him, and probably makes him see things and has an instant effect on his physical appearance.

THAT BEING SAID - there is a possibility he could have come down from that and straddled the line of crazy like Simon did for awhile. After all, Simon said he too went pretty crazy the first time he put it on, and said something that caused Betty to leave. Perhaps something to the tune of, “I am the end and the beginning. I am the hand of madness.”?

But what I really wanted to get to was your point that Simon may not have had an evil bone in his body, something that may be reflected in the Ice King. His only desire is to recover his “princess”, Betty. This originally meant holding back the crown’s influence long enough regain his sanity and get her back. At a certain point he admitted that probably wasn’t going to happen, as he was losing himself. However, he continues his quest. If the Crown augments desires, it took his desire to find a single princess and expanded it to seek and collect multiple princesses. And then use those princesses to conquer the world.

PFFFT- So if the Crown is sentient, that means it and Petrikov had a discussion like this:

And Simon said he wanted his princess back.

And the Crown tried to haggle with him to say he wanted multiple princesses, perhaps because multiple princesses is better than one, and eventually Simon agreed.

Because what the Crown really wanted was for him to build an army and then cover the world in ice. So the friggin’ Crown is stuck convincing him to kidnap princesses over and over, because its Simon’s condition for doing what the Crown wants, the more destructive step. And since Simon keeps failing, partially because his desire is fairly innocent, he remains a fairly ineffective villain. And this was unexpectedly sad.

Also, even if the Crown is presumably telling him to slay his enemies, he doesn’t even want to do it when a hitman is ready to hand them over on a silver platter. As you said, mostly he just hangs around taking care of his penguins and being lovesick over princesses. Which is hilarious but also DESPERATELY SAD.

So with ALL that evil influence bearing down on him, which he may have learned to resist in his time looking for Betty, he’s still a fairly decent guy minus some creepiness. There was just nothing for the Crown to latch onto, unlike Finn.