One possible storyline could be a battle of wits between Leonardo and Tigerclaw. Leonardo, being the leader of the Turtles, would constantly try to outsmart Tigerclaw. For example, he could set up elaborate traps to catch Tigerclaw and stop his evil plans. Tigerclaw, on the other hand, would be constantly trying to anticipate Leonardo's moves and turn them against him. Another storyline could be a more complex relationship where they start to understand each other's motives over time. Maybe there could be a situation where they have to team up against a common, even greater enemy. This could lead to a begrudging respect between them.
One idea could be a story where Leonardo and Tigerclaw are forced to team up temporarily to defeat a common enemy greater than their rivalry. Maybe a new, powerful mutant emerges that threatens both the turtles and Shredder's plans. This would put them in a situation where they have to rely on each other's skills.
The conflict between good and evil is a key element. Leonardo represents the good, and Tigerclaw is clearly on the side of evil. Their clashes, both physical and ideological, can create a lot of tension and excitement. For instance, their different fighting styles - Leonardo's ninjutsu training with Splinter versus Tigerclaw's more brute - force and underhanded tactics. Another element is the mystery around Tigerclaw. There could be parts of his past that are slowly revealed in the fanfiction, which could add depth to the story.
Leonardo would be a likely candidate. He is often the most level - headed of the turtles and believes in honor and justice. He might see the potential for a greater good if he can end the hostilities with Tigerclaw, so he could be the one to make the first move towards a truce.
Another possible main character could be a character with a mysterious origin. This character's past might be gradually revealed throughout the story, adding an element of intrigue. He or she could have powers that are initially hard to understand or control, which creates internal conflict as well as external challenges when dealing with the enemies in the graphic novel.
The ultimates graphic novel may also stand out in terms of its use of color. The color palette could be carefully chosen to set the mood. For instance, darker tones might be used in more serious or menacing scenes, while brighter colors could represent hope or heroic moments. It might also have a distinct narrative structure, perhaps using flashbacks or multiple storylines that converge in an interesting way.
I'm not entirely sure as the title is rather unclear. It could potentially be a fanfic about a character named Hela with some kind of ultimate form, and perhaps the '3610x oc' might refer to an overclocked (oc) setting related to a system or device within the context of the fanfic. But without reading it, it's just speculation.
To write a compelling Leonardo in fanfiction, first focus on his existing traits. He's brave, so show him facing his fears head - on in new and unexpected situations. For example, if he has a fear of heights, put him in a situation where he has to climb a tall building to save someone. Also, explore his relationships. Maybe he has a falling - out with a close friend and has to work hard to mend it, which shows his loyalty and determination.