Typically, it's portrayed as a very deep and affectionate mother - son love. Kushina's love for Naruto is shown as selfless and all - encompassing, even from beyond the grave. Naruto, in turn, has a great admiration and love for his mother that he didn't get to experience fully while she was alive. In some fanfics, this love is also shown through their shared Uzumaki heritage, with Naruto feeling a special connection to his mother because of it.
In such a fanfiction, the relationship between Naruto and Kushina would be one of mother - son love and mutual respect. Kushina would be protective of Naruto and proud of the man he has become. Naruto would look up to Kushina and value her wisdom. With Hinata, Naruto's relationship would be that of a loving couple. Hinata would support Naruto in all his endeavors. When it comes to Kushina and Hinata, Kushina would likely see Hinata as a worthy partner for Naruto and Hinata would respect Kushina for being Naruto's mother and a strong kunoichi.
In many Naruto fanfictions, Minato is often portrayed as an even more brilliant strategist and a loving husband. He might be shown using his Hiraishin no Jutsu in creative ways to protect Kushina. For example, in some stories, he uses it to surprise her with little gifts or to show up just in time when she's in danger.
Many fanfictions explore Naruto's discovery of his mother Kushina's love. Since he grew up without her, when he finally learns about her through memories or other means in fanfictions, it creates a deep emotional impact. The love can be shown as something that gives Naruto more strength and purpose. For example, in some stories, he realizes how much she sacrificed for him and it makes him even more determined to protect the village she loved.
In a fanfiction, Naruto discovers old letters from Kushina that were hidden away. As he reads them, he gets to know a more personal side of his mother and feels an even stronger bond of love towards her. It's a story of connection through words and memories.
In a fanfiction, perhaps Kushina was able to leave a part of her chakra within Naruto when she died. This chakra has memories and emotions of her love for him. As Naruto gets stronger and faces difficult battles, this chakra activates and gives him not only power but also the feeling of his mother's love, which heals his emotional wounds and gives him the motivation to keep fighting.
Some fanfictions portray Kushina's angst through her interactions with other characters in the afterlife. She might be angry or sad when talking to Minato about Naruto, blaming herself or him for their son's difficult life. This shows her internal turmoil and angst in a very direct way.
Often, Kushina's son complex is portrayed as extreme protectiveness. She might jump in to defend Naruto at the slightest hint of danger. For instance, if Naruto is about to face a tough opponent in a spar, she may try to stop it.
The relationship can be shown as a strong mentorship. Kushina, being Naruto's mother, can guide him in understanding his Uzumaki heritage. For example, she can teach him about the significance of their clan's sealing techniques. Naruto, in turn, can show her how the village has evolved since her time, creating a bond based on mutual learning.
Often, their relationship is portrayed as very antagonistic. Lucifer resents Michael for always being the 'favored son' in their father's eyes, and Michael sees Lucifer as the rebellious and disobedient one. So in many fanfictions, they are at each other's throats, ready to fight at any moment.
It could be developed through a series of events where Kushina tries to make amends. She might leave little signs or messages for Naruto, showing her love and regret. As Naruto starts to notice these things, he becomes curious about her true intentions. Eventually, they have a face - to - face encounter where Kushina explains everything. Naruto, seeing her sincerity and the love she has for him, forgives her, and they start to build a new, stronger relationship based on honesty and understanding.