Unlike in other parts of Nigeria, the engine of British colonization faced especially stiff resistance in the lower Niger. Since the mid 19th century, the Royal Niger Company, a nationalized British trading corporation, had been creeping slowly along the banks of the Niger, leaving in its wake a trail of deceit, humiliation, intimidation, and glaringly one-sided treaties. In 1870, after much conflict, Ndoni, a powerful Igbo-speaking trading kingdom and naval power whose formidable fleet of war canoes virtually controlled trade in the lower Niger, was conquered by the Royal Niger Company, forever tilting the balance of power in the region. By the 1880s, the British and their Christian missionaries had established a regional stronghold at Asaba.
In the 1890s, radical local leaders, who had formerly held power in native politics, but had become disenfranchised in the new British-organized colonial structure secretly convened throughout the Anioma region (western Igboland) and shared their collective fears regarding the loss of their independence and the growing influence of European intruders. They organized a secret militia comprised of ordinary young men from all segments of society united in their hatred of Westerners, Christianity and European influences and laid the foundations for what would become an over twenty year struggle known as the Ekumeku Movement.
The Ekumeku, or Silent Ones, united the western Igbo and allowed them to overcome the disadvantages of their fragmented political systems and operate with a single military muscle. Unlike a conventional war, the movement was mainly underground and was spearheaded by secret-society members who were experienced in law administration, war, and policing. Employing guerilla tactics, under the cover of darkness they attacked colonial officials and their local sympathizers, burned and destroyed colonial buildings and posts owned by the Royal Niger Company, and disappeared back into their forest hideouts by daybreak. The manner of impunity and ferociousness with which the Ekumeku operated struck fear in the minds of locals and Europeans alike, earning them the nickname Ikuku
In 1898, the Ekumeku attacked Igbuzo (Ibusa), a town under British occupation, and forced the Royal Niger Company and its employees to flee back to their headquarters at Asaba. In various raids conducted around Asaba, which was not directly attacked because of its fortifications, countless numbers of missionaries, Europeans, and their African supporters were slain, and the movement grew in popularity as increasing numbers of young men swelled into its ranks. It was particularly difficult for the British to combat the Ekumeku mainly because of its faceless and discrete nature; since it had neither public representatives nor a physical headquarters, no no one could be arrested, blamed, or held responsible.
In 1902, stirred into action by rumors of a fresh Ekumeku offensive, the British launched a preemptive strike and arrested dozens of local leaders, chiefs, and elders, who were suspected Ekumeku agents and razed numerous communities to the ground. In that same year, the Ekumeku were defeated at Ubulu Uku and over three hundred men were captured and sent to prisons in Calabar, where many committed suicide or died of disease. Of this number only five were said to have survived. By 1909, the Ekumeku had reorganized at Ogwashi Uku and liberated the town from British occupation. After months of siege, the town once again fell and the Ekumeku were once again dispelled. In the following decade, countless arrests, trials, and hangings eventually signalled the end of anti-colonial resistance in this region.