Karuna holds one of Avalon's two vice-captain positions within Gundam Battle Nexus Online (GBN), sharing leadership duties equally with Emilia. He pilots the Impulse Gundam Lancier, a custom Gunpla he personally designed and built.

He radiates cheerful enthusiasm, frequently becoming overly excited and carried away during virtual activities. This exuberance often draws cautionary warnings from fellow vice-captain Emilia, though her admonitions rarely temper his spirited behavior.

A key example of his personality unfolded during the Nadeshiko-athlon event. Misinterpreting Karuna's offhand comment about her earrings not suiting her as doubt in her ability to win – when he meant only the earrings themselves – Emilia entered the competition. The misunderstanding sparked from Karuna's remark as she viewed a pop-up ad for the event reflected in a surface.

Karuna maintains a visible presence in Avalon, appearing alongside Emilia in promotional materials like the series' second opening sequence. Within Avalon's command structure, he operates in a supportive role under leader Kyoya Kujo.