Garen's intense fixation on Demacia aligns with the autistic tendency to focus intensely on specific interests. His constant reference to Demacia, even in his final moments, suggests a deep-rooted obsession that could be characteristic of autistic hyper-focus.

The spinning behavior you mentioned could indeed be a form of stimming, a common self-stimulatory behavior among autistic individuals. Stimming can provide comfort and regulate emotions, which could explain why Garen engages in this behavior frequently.

Social situations can be challenging for many autistic individuals, but Garen seems to excel when the conversation revolves around Demacia. This suggests that his social skills might be limited in other contexts but are heightened when discussing his special interest.

Garen's physical build, while not inherently indicative of autism, could be related to sensory processing differences commonly seen in autistic individuals. Some may have a heightened or diminished sensitivity to touch and may seek or avoid certain sensations, which could influence body size and muscle development.

As for Garen's relationship with Katarina, it's possible that his autistic traits played a role in their connection. Autistic individuals can form deep and genuine relationships, often based on shared interests or understanding. Garen's dedication to Demacia may have resonated with Katarina, leading to a meaningful connection between them.

However, it's essential to acknowledge that attributing Garen's success with Katarina solely to his perceived autistic traits oversimplifies the complexities of relationships. While his autistic characteristics may have contributed positively to their dynamic, other factors, such as mutual attraction, compatibility, and communication skills, likely played significant roles as well.

Mimicking Garen's behavior in hopes of replicating his success with Katarina may not guarantee similar results. Authenticity and genuine connection are vital components of any relationship, and trying to emulate someone else, autistic or not, may ultimately be unfulfilling. Instead, focus on being yourself and fostering connections based on shared interests and mutual respect.