Koduck inhabits the Pokémon Resort, a relaxing island destination for Pokémon. Naturally shy and reserved, it initially maintains distance from both humans and other Pokémon. This reserved nature stems from apparent social anxiety, causing it to avoid interactions and the resort's common group activities.

Koduck's development charts its gradual bond with Haru, the resort's human concierge. Their friendship has tentative beginnings, marked by Koduck's initial wariness. Through Haru's repeated gentle and patient encouragement, Koduck slowly overcomes its hesitancy. This progression involves cautious steps: first tolerating closer proximity to humans, and eventually engaging in simple shared activities like swimming or relaxing near Haru.

Over time, Koduck exhibits growing ease within the resort. This includes participating more openly in recreational activities and showing reduced signs of distress around unfamiliar company. Its central relationship with Haru serves as the catalyst for this growing confidence, portraying Koduck's journey from isolation toward tentative social integration through its resort interactions.