Behind the curtains.

This here has nothing to do with erotica, but people who like the writing might enjoy this. Besides, looking at the inside of a watch, taking it apart, and examining all the gears, will make for good practice.

This section will be very spoiler heavy, and will detail the sorts of themes and ideas behind the various branches.

Broadly speaking, Ikarus is a character steeped in Duality and Contradictions. The essence of a demon, and the upbringing of a human. With the start of 2.4, this should become more clear as it's the first route where he strongly starts towards humanity. Up until that point the routes have primary shown him choosing to embrace his demonic heritage in various ways.

Many of the bad ends, and there are many bad ends, come from the conflicting parts of his personality asserting themselves or from him showing different faucets to the wrong people and making them act in ways that are detrimental to his survival.

In other words, trying to live somewhere between his two natures is often a path to disaster. Being forceful where he's usually chosen stealth, or choosing insecurity over self-assurance when he's primary used one over the other.

That said, there are bad ends where the responsibility is primarily owed to another and the most common agent of this is the Exciser. She's much stronger than Ikarus here and most active in 2.1 and it's derivatives. If Ikarus lingers in the area after killing May's family, she's almost guaranteed to appear and put an end to him. The issue for Ikarus, other than lacking the means to face her directly, is his ignorance of her. Every time she's appeared in a 'demon' path, she's an active **** that Ikarus has to react to.

That said, she's not infallible. In the 2.2 branch, Ikarus spends enough time hidden and unknown that the Exciser passes him by and has lost his trail. As long as he remains largely covert, it's unlikely for her to return. In the 13.2 branch, the circumstances has left her ignorant of the danger and too far away to head off Ikarus.

But she's not the only danger to Ikarus, and one thing I've always enjoyed in a story is when characters clear act outside the view and knowledge of the leads. Ikarus isn't omniscient, he doesn't truly understand the thoughts and motivations of others. He can guess, he can manipulate, and he can use his abilities to make his assumptions reality, but he's often wrong and that can lead to disaster. If he's exposed, it can become very dangerous and difficult for him to change lanes and in branches where Ikarus becomes reactive, those are often places where he'll meet a bad end.

Characters like Thag, the Exciser, and the Witch each present a danger in this vein. Thag's instability can lead to Ikarus losing initiative, scrambling to keep up. The Witch, when dominated, is more subtle is seizing initiative but no less dangerous for that.

To summarize, for Ikarus to be successful in a route, I believe he would have to be consistent in his choices, knowledgeable in his surroundings, and consistently proactive; or lucky.