Sirius Black's Potential Reaction if He Knew About Snape’s Involvement

In the context of the Harry Potter universe, the relationship between Sirius Black and Severus Snape is one of the more complex and fraught. If Sirius were to discover the extent of Snape's role in the deaths of his best friends, James and Lily Potter, his response would likely be intense and violent.

Immediate Frustration and Anger

Given how Sirius tracked down and attempted to apprehend Peter Pettigrew (Av impulsively and singlehandedly), it's reasonable to assume that he would be exceptionally angry if he knew about Snape's actions. Considering his previous fervor in pursuing Peter, it seems unlikely that the Dementors' presence in Azkaban would significantly alter his course of action. His anger would likely manifest not just in verbal protests but in physical violence aimed at Snape.

The immediacy of his reaction would likely drown any rational thought, leading him to act on pure emotion. This could manifest in various ways, from physical violence to a desire for retribution that borders on vengeance.

Justification for His Actions

Many would argue that Sirius's response would be justified. Snape, as the Potions Master and Double Agent, played a critical role in orchestrating the Potter family’s demise. The revelation of his role in their deaths would incite an intense desire for justice from Sirius, bordering on a need to avenge their murders.

Potential Actions Sirius Might Take

Given Sirius's track record, he might take several drastic, perhaps even illegal, actions. One such possibility is sending Harry away from Hogwarts, as he did in some fanfiction scenarios, sending him to Beauxbatons. This action would reflect a desire to sever Harry's ties to a place that reminds him of his failure to protect his friends.

However, it’s important to note that this action alone would not fully address Sirius’s feelings of inadequacy and rage. He would likely continue to seek vengeance against Snape, believing that the only way to avenge his friends is by directly confronting and punishing Snape.

The Role of Albus Dumbledore

Between Snape and Dumbledore, Sirius might feel a particularly strong sense of betrayal. In the canon, Dumbledore often made decisions that sometimes seemed to go against the better judgment of his supporters. Here, Dumbledore’s decision to hire Snape and appoint him to the Order of the Phoenix might be seen as a grave mistake. This decision not only allowed Snape to continue his double life but also potentially facilitated the deaths of the Potters.

For Sirius, Dumbledore’s failure to convince the Potters to use him as Secret Keeper would be seen as yet another example of Dumbledore’s flawed judgment. If given the chance, Sirius would undoubtedly have taken the role of Secret Keeper himself, reasoning that he could have been a more reliable protector.

Given the above, it’s clear that Sirius would have wanted to kill Snape, not just verbally condemn him. His desire for vengeance would be rooted in a belief that Snape’s actions directly led to his friends’ deaths and his failure to protect them. This belief, combined with his previous failures, would fuel his intense anger and his willingness to go to extreme lengths to achieve justice.

In summary, Sirius's reaction would be one of intense anger and frustration, potentially leading to him wanting and possibly attempting to kill Snape. His actions and motivations would reflect a profound sense of betrayal and a deep-seated need for revenge.