* Thematic Resonance: Does killing Tyrian with a werewolf emphasize themes of primal rage, untamed power, or nature's vengeance? Does a fairy killing him highlight themes of betrayal, internal conflict within the fairy realm, or a clash of magic systems?
* Character Development: Which killer would provide the most satisfying and impactful character arc? Would the werewolf's killing be a desperate, animalistic act, or a calculated revenge? Would the fairy's killing be a cold, calculated act of justice, a reluctant sacrifice, or a display of newfound power?
* Plot Implications: How would each killer's actions affect subsequent events? Would a werewolf's involvement lead to further conflict with werewolves? Would a fairy's involvement unravel political alliances or ignite a war within the fairy court?
* Tyrian's Character: Consider Tyrian's personality and actions. Who would be his most fitting nemesis? Would a battle with a powerful werewolf be a fitting end for a physically strong, violent antagonist? Or would a more cunning fairy be a better match for a manipulative and deceitful character?
Ultimately, the best choice is the one that best serves your story. There's no objectively "better" option. Weigh the pros and cons of each scenario based on the factors above and choose the outcome that feels most organic and impactful for your narrative.