She could try to appeal to Sasuke's emotions. If she can remind him of their past, of the times they fought together and cared for each other, it might make him release her. Sakura could talk about their shared experiences and how they are on the same side deep down, hoping to break through whatever is making Sasuke hold her captive.
One possible fanfiction could be about Sasuke using his Susanoo to save Sakura from a dangerous enemy. In this scenario, Sasuke, seeing Sakura in peril, quickly activates his Susanoo. The powerful, spectral form of the Susanoo reaches out with its massive hand and grabs Sakura, pulling her to safety. This moment could be a turning point in their relationship, with Sakura realizing anew how much Sasuke still cares for her, despite their past differences.
A fanfic could explore what if Naruto and Sasuke were fully aware of their Indra and Ashura identities from the start. Maybe they are born with memories of their past lives. This would completely change their relationship dynamic. They could be more united from the beginning, working together to reform the ninja world according to the will of their predecessors. They might introduce new jutsu and ninja teachings based on the ancient knowledge of Indra and Ashura, which would face opposition from the traditional ninja clans who are resistant to change.
One possible scenario in this fanfiction could be that Sasuke's Susanoo hand captures Sakura in a moment of intense battle. Maybe it's not an act of aggression but rather an attempt to protect her from an unseen enemy. The Susanoo's power is so great that when it reaches out to grab Sakura, it creates a sense of both danger and safety at the same time. She might initially be startled but then realizes Sasuke's intention.
There could be a fanfiction where Sasuke grabs Sakura with Susanoo during a chaotic event like a village - wide attack. The Susanoo's large form is able to cut through the chaos and reach Sakura just in time. Afterward, they have to work together to fend off the attackers. This shared experience could strengthen their relationship and make them more open to each other about their feelings and intentions.
A great Naruto Sasuke Ashura Indra fanfiction might focus on the powers they possess. Ashura and Indra had unique abilities, and imagining how Naruto and Sasuke could inherit or be influenced by these in new ways can be exciting. For instance, Sasuke could gain a deeper understanding of Indra's power and use it to create a new jutsu that combines both his own skills and the ancient power, which would make him even more formidable in battles against new threats.
Some fanfictions might explore how Ashura and Indra's past actions could have different impacts on Naruto and Sasuke. Maybe in a fan - made story, Indra's actions in the past were misinterpreted, and Sasuke has to figure out the truth. This could change his entire perception of his own power and destiny.
In this fanfiction, it might be that Sakura is physically restrained within Sasuke's Susanoo hand. She could be struggling against the power of the Susanoo itself, like it's draining her energy or causing her pain. And she has to find a way to either escape or get Sasuke to release her on his own.
One possible reason could be that Sasuke is being influenced by some dark force. Maybe it has corrupted his mind and made him see Sakura as a threat to his new goals, whatever those might be in this fanfiction's plot. So, he uses Susanoo to hold her captive as a way to neutralize that threat.
The power dynamics between them. Since Indra was known for his power and Sasuke has always been a strong character, and Naruto as Ashura is also very powerful. Their battles and how they balance each other's powers would be important. For example, when they fight side by side, how they combine their different chakra natures and jutsu.