Keera L. Greenwood served as crown prince of the elven Kingdom of Greenwood and was the older brother of Shera L. Greenwood. He possessed long blonde hair styled in a Hime cut and blue or cyan eyes. Accounts described his youth as that of a sweet and loving brother who played and laughed with Shera, though some suggested this kindness may have been a facade hiding his true nature. Over time, Keera embraced fanatical racism against all non-elven races and developed an obsessive, incestuous fixation on his sister Shera. His core motivation became forcing her to bear his child to continue the royal bloodline, disregarding her clear objections. This drove him to place a bounty on her after she fled.

Tracking Shera to Faltra City where she resided under Diablo's protection, Keera initially presented himself as a remorseful brother concerned for her wellbeing, lowering suspicions through this deception. He soon revealed his manipulative intent, employing an enchanted flute capable of compelling five-minute listeners to obey. Using this ability, he controlled Shera's mind and forced her to return with him to an elven encampment. There, he imprisoned her within his tent, chaining her. Keera interrogated Shera about Diablo's use of her slave collar, flying into a rage upon learning Diablo had not sexually exploited her. During this encounter, he summoned a fabric-dissolving slime to strip Shera naked, laughing at her paralysis while openly stating his intent to rape her, which he rationalized as "foreplay."

Confronted by Diablo, Rem, and Alicia, Keera's true personality emerged: smug, arrogant, petty, cruel, quick to anger, and prone to abusing subordinates. He demonstrated cowardice by hiding behind guards and summoned Greenwood's secret weapon, the Force Hydra—a level 100+ four-headed dragon capable of breathing flame, ice, wind, and sand. Despite boasting control over this entity, he failed to direct it effectively in combat. After Diablo destroyed the Hydra, Keera begged for his life and attempted to flee, only to be beheaded by Lieutenant General Chester Ray Galford. His death was justified as retribution for openly declaring war, smuggling troops into Faltra, and threatening civilians.

Keera consistently overestimated his abilities while habitually underestimating others, dismissing opponents as "stupid" and viewing basic decency as weakness. He harbored contempt for his "feeble" father and resented his deceased elder brother—hinting he caused the brother's suspicious "hunting accident." His worldview centered on personal entitlement, leading to reckless decisions like camping visibly in enemy territory and triggering international incidents through poor judgment. His final moments exemplified his inability to comprehend consequences despite repeated warnings about violating laws and norms.