Levi gave the injection to Armin to save his life by turning him into a Titan, specifically a Colossal Titan, a critical decision made over saving Erwin. This choice was driven by a complex assessment of what would best serve humanity's long-term future.
The Pivotal Decision
During a critical moment following the bloody battle against the Beast Titan, Levi found himself with a single titan serum. He faced an agonizing choice: use the serum to revive the gravely injured Commander Erwin Smith or the severely burned Armin Arlert. Both were vital to the Survey Corps, but only one could be saved by inheriting a Titan power.
Prioritizing Humanity's Future
Ultimately, Levi made the profound decision to save Armin. This choice went beyond mere immediate victory. Levi's rationale was rooted in the belief that Armin represented the preservation of humanity's potential for change. While Erwin was a brilliant tactician and charismatic leader who had pushed humanity forward, Levi seemed to believe that Erwin's journey had reached its natural conclusion, and that Armin, with his unique strategic intellect and different perspective, offered a fresh hope for the future.
- Strategic Brilliance: Armin had consistently demonstrated exceptional analytical skills and strategic thinking, often devising plans that saved the Survey Corps from seemingly insurmountable odds.
- New Perspectives: Unlike Erwin, who was burdened by his singular lifelong dream and experiences, Armin was seen as having the capacity to adapt and innovate in new ways.
The Consequence of the Choice
By injecting Armin with the titan serum, Levi effectively granted him a new life as a Colossal Titan. This act, however, simultaneously meant sacrificing Erwin's life, allowing him to finally rest after years of immense sacrifice and burden. Armin's transformation provided the Survey Corps with a new, powerful asset in their fight against the Titans, while also ensuring the continuation of a mind capable of groundbreaking strategic insights for humanity's survival.
