In Harry Potter, Severus Snape's Doe Patronus not only reveals that he is in love with Lily Potter, but also helps Harry find the Sword of Gryffindor.
However, this is just the tip of the iceberg.
When Snape reveals his Patronus to Dumbledore, it becomes the most iconic scene in the entire Harry Potter series.
In particular, Alan Rickman's simple phrase "forever" is impressive.
But in reality, there is much more to this scene behind it, which has a profound impact on Harry's fate.
Harry first learned about the concept of a Patronus during Harry Potter and the Prisoner of Azkaban, but the spell is not explained in much detail in the films.
According to the premise in **, only truly gifted wizards can create a Patronus with an animal entity - a large percentage of wizards can only breathe a cloud of silver mist from their wands.
Also, wizards can't choose what their patronus looks like, but the animal has always had a strong connection to the wizard's inner world.
In other words, the Patronus changes with the emotions of the owner - a very important detail that was missed in the film version of Harry Potter.
The change in the Patronus had a significant impact on Severus Snape's fate, which is why in Harry Potter and the Deathly Hallows, when Snape summoned the Patronus of the Deer, it shocked Dumbledore so much.
After all, even the strongest wizards can't decide what their Patronus will become.
In other words, the Patronus is the least lying, and it is the truest portrayal of your heart.
Snape's Patronus is a deer, similar to Lily Potter's.
Although it is not explicitly told whether Snape's Patronus has always been this way, or if it has since changed.
However, considering how surprised Dumbledore was when he saw Snape's Patronus, it should be more likely that his Patronus would change.
Especially in "Harry Potter and the Half-Blood Prince", when Tonks falls in love with Remus Lupin, her patronus changes from a hare to a wolf.
So, we can speculate that Snape may have been in a similar situation.
Even when Lily later reunites with her nemesis, Snape's love never changes.
In Harry Potter and the Prisoner of Azkaban, Dumbledore tells Harry that his dead relatives never left him.
When Harry summons the Stag Patronus, it seems to be in a way that his father, Jaime, is still protecting him.
So, if the same assumption applies to Snape, and his Patronus becomes a doe like Lily, does that mean he continues to guard her son for Lily?