Among the latest entrants is Micah Kigen, popularly known as Kagoech, a former close ally of former ODM leader Raila Odinga.
Kigen said he was pushed into the contest by residents and has chosen to seek the UDA ticket, the dominant political vehicle in the region, setting the stage for a potentially bruising primary battle.
“I am in the race to create a difference in terms of leadership and development for the people of Keiyo South,” he said.
His entry adds another layer to an already crowded contest, with Kigen seeking to distinguish himself by making development, jobs and investment the centre of his campaign.
He has accused the current leadership of relying on what he described as name-calling, abuse and arrogance, arguing that such politics does little to address the economic concerns of residents.
“They assume voters are interested only in handouts and personalities rather than jobs, investment and better leadership,” Kigen said.
He spoke at Kaptagat, where he launched Keiyo Queens, a women-led grassroots movement seeking to support his bid across the constituency’s six wards.
The movement gives Kigen an early grassroots platform as he attempts to build support beyond his immediate political base and translate his message of change into an organised campaign.
“Our people understand jobs, farming, business and whether their children have a future. Development is not too complicated for the people of Keiyo South.”
Kigen is presenting the contest as a choice between personality-driven politics and a development-focused approach, placing economic opportunity at the heart of his challenge to Kimaiyo.
He argues that Keiyo South has considerable land, agricultural potential, mineral resources and human talent but has not fully converted these advantages into opportunities for residents.
According to Kigen, the challenge is not a lack of resources but the failure to organise and pursue investment and government opportunities that could create jobs and expand economic activity.
He has also sought to align his campaign with President William Ruto’s development agenda, saying the region should position itself to benefit from opportunities being pursued by the national government.
“We cannot just watch opportunities pass us by. We must organise, develop serious proposals, knock on the doors of government and investors and ask: what is in it for Keiyo South?” he said.
Kigen has particularly targeted women, arguing that unemployment and weak household incomes have a direct impact on families.
He said women have a particular reason to demand change because they bear the consequences of unemployment, including educated children unable to find work and households struggling without reliable incomes.
His campaign is therefore attempting to broaden the debate beyond the personalities competing for the seat to issues of household welfare, employment and economic opportunity.
But translating those concerns into votes will be the central challenge for all the aspirants seeking to unseat Kimaiyo.
The incumbent has vowed to seek reelection, meaning the incumbent will have to defend his record while navigating a crowded field of challengers, many of whom are likely to seek the same UDA nomination.
Among those also eyeing the seat are Alex Rotichand Lawi Kibire, a former speaker of the Elgeyo Marakwet county assembly.
The number of aspirants could increase the pressure on Kimaiyo but could also fragment the anti-incumbency vote if his challengers fail to rally behind a single candidate.
For the rivals, the challenge will be to convert individual ambitions into a sufficiently broad coalition capable of defeating an incumbent in the party primaries.
For Kimaiyo, the task will be to demonstrate that he retains the grassroots support necessary to survive a crowded nomination contest.
With the UDA ticket likely to carry considerable weight in the constituency, the contest is shaping up as a test not only of the incumbent’s popularity but also of the strength of the networks and mobilisation machinery being assembled by his challengers.
