One characteristic is their unique abilities. For example, in 'Overlord', the MC has abilities that are far beyond normal characters in the game - turned - real - world setting. Another is their rapid growth or high starting level. In 'Sword Art Online', Kirito starts with a good level of skills which he further hones.
One great light novel with a powerful main character (MC) is 'Overlord'. The MC, Ainz Ooal Gown, is extremely OP (overpowered). He starts as a max - level character in a game world that has suddenly become a reality. His abilities and strategic mind make him nearly unbeatable.
One great OP MC (Overpowered Main Character) fantasy light novel is 'Sword Art Online'. The main character, Kirito, is extremely skilled and powerful in the virtual world of Aincrad. Another is 'Overlord'. Momonga, the main character, is a very powerful magic caster in a game world that has become a reality. Also, 'That Time I Got Reincarnated as a Slime' is good. Rimuru starts as a slime but quickly gains incredible powers and builds his own nation.
The light novel 'Akame ga Kill!' also has an OP female MC in Akame. She is a highly trained assassin with a powerful teigu (a special weapon). Her skills in combat and stealth are top - notch, allowing her to take on much stronger opponents.
One great anime is 'Sword Art Online'. The main character, Kirito, is extremely overpowered (OP). He is highly skilled in the virtual reality world of SAO. In the series, he also has a love story with Asuna. Their relationship develops as they face various challenges together in the dangerous game world.
In light novels, 'op mc from start' often refers to an overpowered main character right from the beginning. This means the character has abilities, skills, or knowledge that are far superior to others at the start of the story, which can lead to some really interesting plot developments as they either face challenges despite their power or use it to quickly rise in their fictional world.
I'm not entirely sure as there could be many light novels with an OP (overpowered) main character (MC). It could be about a hero in a fantasy world who has extraordinary powers and uses them to overcome various challenges.
They usually have a strong sense of justice or a unique goal. Take Luffy from 'One Piece' (which also has light novel adaptations). His goal of becoming the Pirate King drives him forward, and his rubber powers along with his unwavering will make him overpowered in his own way. He stands up against strong enemies to protect his friends and achieve his dream.
A best OP MC can also be defined by their relationships. In light novels like 'Re:Zero', Subaru has his Return by Death ability which is OP in a sense. But it's his relationships with the other characters, his love for Emilia, and his growth through his interactions that make him a great MC. The way an MC interacts with the world around them, whether it's a fantasy or sci - fi setting, and how they use their powers to either uphold or subvert the norms of that world also contribute to them being considered 'best' and 'OP'.