In fanfiction, with complete control of blood, Naruto could have a new form of healing. He could control the blood flow to injured areas more precisely, accelerating the healing process. Also, he might be able to detect the presence of enemies by sensing their blood, like a kind of blood - based radar. This would give him an edge in both offensive and defensive situations.
If Naruto has complete control of blood in fanfiction, it would likely change his relationships as well. His friends might be in awe of this new power, but also a bit wary. Enemies would definitely fear him more. He could use this power to protect his village in ways no one had ever imagined. For instance, he could create blood barriers or use the blood of defeated enemies as a warning to others. His newfound ability would also attract the attention of other powerful characters in the Naruto universe, leading to new alliances or rivalries.