As an assassin, Harry would use magic in a very different way. He could use the Apparition spell not just for travel between places but also to quickly escape from a dangerous situation after an assassination attempt. The Levitation Charm could be used to move objects around to create distractions or set up traps for his targets. Also, he might modify spells like the Fire - Making Spell to create more intense and dangerous fires to either destroy evidence or attack his enemies. His magic would be less about showing off or helping others like in the original story and more about achieving his assassin - related goals.
He would probably use magic for more practical and lethal purposes. For example, the Imperio curse could be used to control his targets, making it easier for him to complete his assassinations. The Disillusionment Charm would be crucial for him to blend into the shadows and get close to his victims unnoticed. And he might also use the Stunning Spell not just to incapacitate, but perhaps as a precursor to a more deadly attack.
He would probably learn some basic self - defense magic first. Tsunade would want Harry to be able to protect himself, so things like a simple shield charm or a disarming spell would be among the first. Since she is also good at medical techniques in her world, she might also introduce Harry to some basic healing magic early on.
If Harry is raised by Sesshomaru, the magic he learns would be a blend of wizarding magic and something more influenced by Sesshomaru's world. He could learn to use his magic in a more silent and stealthy way, as Sesshomaru is often a silent predator. His magic might also be more attuned to nature, as Sesshomaru has a connection to the natural world in his own realm. Harry might be taught to use magic to create illusions not just for fun but as a serious combat tactic, and he could learn to manipulate his magic in ways that are more fluid and less structured than traditional wizarding magic, allowing for more creative and unexpected attacks.
He would probably learn basic but very powerful defensive magic first. Merlin would know the importance of protecting oneself, so things like a strong Shield Charm or basic protective enchantments would be among the first things Harry learns.
One way could be through summoning magic. He summons the necessary elements like earth, stone, and trees from different places in the wizarding world. Then, he uses a combination of spells to bind them together and create an island. This would require a great deal of magical energy, but Harry, with his powerful magic and the help of his friends, could manage it.
Harry would likely learn dark magic. Bellatrix is a master of the dark arts, so she would teach Harry curses and hexes that are not typically taught at Hogwarts. He might learn how to use the Cruciatus Curse effectively, for example.
His magic could be more combat - oriented. Jiraiya's ninja background would likely influence Harry to use magic in a more direct and aggressive way in battles, rather than just for defensive or utility purposes like in the original series.
In such a fanfiction, perhaps Harry would grow up with a different kind of magic. Lady Magic could endow him with unique powers. He might have a more in - depth understanding of magic from a very young age, and his relationship with the magical world could be more profound than in the original story.
A natural healer in the Harry Potter world might use Herbology - based magic. They could use plants like dittany which is known for its healing properties on wounds. By chanting simple spells over the plant extracts, they could enhance their healing powers. For example, a spell to accelerate the dittany's ability to close a wound quickly.
The magic training Harry would get in this fanfiction scenario would be very distinct. Ra's al Ghul would train Harry to use magic as a weapon first and foremost. Harry would be taught spells that are not typically part of the Hogwarts curriculum. He might learn how to create magical traps, how to use magic to enhance his physical abilities like speed and strength, and how to use magic to read an opponent's weaknesses. His training would be more about survival and domination rather than the academic and sometimes whimsical magic taught at Hogwarts.
His magic might be darker. The environment of Arkham Asylum is full of negative energy. So, it could taint his magic in some way, making it more aggressive or unpredictable.