Well, one characteristic could be the focus on a more 'romantic' or 'intimate' relationship between Luffy and Ace, which is often not in line with the original platonic nature of their bond in the source material. However, this is a very controversial aspect as it goes against the typical portrayal of their brotherly relationship.
One thing to avoid in ace and luffy lemon fanfiction is the deviation from the original essence of their relationship. In the official One Piece story, they are comrades and brothers. 'Lemon' fanfictions often introduce adult themes that are not in line with the pure and adventurous spirit of their bond. Also, such fanfictions may objectify the characters, which is disrespectful to the original creation.
I'm sorry but 'lemon' in fanfiction often refers to adult or sexual content, which is not appropriate to promote. However, there are many great non -'lemon' fanfictions about Ace and Luffy. You can try looking on platforms like Archive of Our Own (AO3) and filter for general adventure or friendship - themed stories between them.
I'm not really into lemon fanfiction as it often contains inappropriate content. However, you can try looking on some popular fanfiction websites like Archive of Our Own. They have a wide range of fanfictions about Luffy and Ace, but you should be cautious and avoid any works with inappropriate themes.
Well, 'Luffy and Ace: Unbreakable Ties' is a fanfiction that I really like. It focuses on their childhood memories and how those shaped their relationship as they grew up. There's also 'Ace and Luffy's Great Escape' which is full of action. It shows their cleverness in getting out of difficult situations. 'Luffy and Ace: The True Friendship' is a must - read too. It simply and effectively shows the depth of their friendship.
One great 'Ace Protective of Luffy' fanfiction is 'The Unbreakable Bond'. In this fic, Ace is always on high alert to protect Luffy from any threats in the New World. He uses his fire powers in really creative ways to fend off enemies.
Character development is key. Fanfictions explore how Ace and Luffy grow under Garp's influence. Maybe Luffy becomes more disciplined in some stories, or Ace learns to be more open - hearted, all thanks to their interactions with Garp and each other.
One great 'Ace Sabo Luffy Fanfiction' is 'The Brothers' Bond'. It beautifully explores their relationship, showing how they support each other through various challenges. Another one is 'Sabo's Return'. It focuses on Sabo coming back into Luffy and Ace's lives and how they all readjust. There's also 'Ace and Luffy's Adventure', which takes the three on a fictional journey filled with action and heartwarming moments.
In a fanfiction, Ace's own experiences and battles could be related to Luffy's metabolism. Maybe Ace has some knowledge about a special fruit or power that could enhance Luffy's metabolism. He could share this with Luffy, leading to a new adventure where Luffy tries to obtain this thing to boost his metabolism. Also, Ace's death could have an impact on Luffy's metabolism. Luffy could go into a state of shock or extreme grief that either slows down or speeds up his metabolism in an unexpected way.