Kelb commanded the Royal Army under King Gilgamesh, spearheading forces during the Summer of Anu campaigns to purge monsters from the Tower of Druaga and defeat the demon Druaga. Holding high military authority, he previously mentored Ahmey during their shared army service. Initially dismissive of non-military climbers like Jil due to his belief in the army's supremacy, Kelb's perspective shifted as he witnessed the Royal Army's limitations against the tower's perils and Druaga's true threat, leading him to recognize the climbers' potential value.

Following Druaga's second defeat, Kelb resigned from the Royal Army over King Gilgamesh's false claim of victory. He transitioned to civilian life, establishing and operating a tavern near the tower. There, he provided shelter and support to Jil and Fatina, allowing them to recover from betrayal and hardship. The appearance of the girl Ki and rising political tensions prompted him to leave his tavern with employees and investigate the truth behind Gilgamesh's immortality and the connections linking Ki, Kaaya, and the tower itself.

His investigation uncovered Gilgamesh's curse and the emergence of Shadow Gilgamesh. Aligning with the rebellion led by his former comrade Ethana against the king's tyranny, Kelb played a crucial role by delivering vital reinforcements to Uruk. During the climactic conflict, he confronted and defeated King Gilgamesh's true body while Jil and Kaaya battled the shadow manifestation. After the rebellion succeeded and the tower's threats ended, Kelb married Ethana, concluding his military and rebellious path to begin a peaceful life together.