The looming trouble is also likely to hit former President Uhuru Kenyatta’s Jubilee Party.
Gachagua has intensified efforts to market DCP as the region's political home.
He has welcomed governors, former and aspiring MPs, MCAs and grassroots leaders crossing over from rival parties.
His latest announcement saw him receive Nyandarua Governor Kiarie Badilisha alongside 24 sitting MCAs from Laikipia and Nakuru counties, whom he said had abandoned UDA and its affiliate parties.
"The mass exodus from UDA, TSP and other wheelbarrow outfits to DCP is gaining momentum, and by December they will be mere shells," Gachagua declared at his Wamunyoro residence.
While the statement targeted President William Ruto's ruling party and its allies, the ripple effect is increasingly being felt across the political divide, with both Kenya Kwanza affiliate parties and united opposition outfits facing an uncertain future.
Some of the outfits with roots in Mt Kenya include Jubilee Party, the Democratic Party, People’s Liberation Party, Party of National Unity, Chama Cha Kazi, Tujibebe Party and “Mbus” Party.
Among the biggest casualties is Justin Muturi’s Democratic Party, which had briefly emerged as a formidable opposition vehicle in Embu during the 2025 Mbeere North MP by-election.
The party fielded Newton Karish as the opposition's consensus candidate after rival parties agreed to back a single contender against UDA.
However, Karish who lost the election has since joined DCP.
This week, Gachagua unveiled former Evurore MCA Duncan Mbui as DCP's candidate for the Mbeere North parliamentary seat in 2027, while Karish is expected to contest the Embu Senate seat on the same party ticket.
The move effectively brings together two of the strongest anti-UDA politicians in Mbeere under one party.
The 2025 by-election was decided by a razor-thin margin after UDA candidate Leo Wamuthende polled 15,802 votes against Karish's 15,308 in the controversial poll.
Mbui, who had initially sought the DCP ticket, ran as an Independent and garnered 2,480 votes.
The opposition blamed the split vote for handing UDA victory.
Mbui is one of the most influential politicians in Mbeere after winning the Evurore MCA seat as an Independent in 2022, defeating UDA despite losing the party nomination.
The latest arrangement means DCP will field one candidate for each major elective seat in Embu, with Mbui for Mbeere North, Karish for Senate and Gitonga Mukunji expected to challenge Governor Cecily Mbarire.
Embu was previously seen as a DP backyard.
Mwangi Kiunjuri’s The Service Party (TSP), another Kenya Kwanza affiliate with a presence in Mt Kenya, has also come under increasing pressure.
Gachagua has repeatedly singled out TSP among the “wheelbarrows” he says will be emptied by the growing wave of defections to DCP.
He has also turned his attention to reports of a possible new political party associated with Kiharu MP Ndindi Nyoro.
Without naming Nyoro directly, Gachagua recently vowed to "smoke out" what he described as a new "wheelbarrow" being assembled in Murang'a.
Even parties within the opposition are beginning to express concern over the changing political landscape.
Jubilee Party deputy leader Jeremiah Kioni has warned against attempts to create what he described as a one-party political system, insisting that Kenyans must be allowed to choose leaders from different political parties.
Speaking during a meeting with Jubilee aspirants, Kioni said the party would continue preparing candidates for the 2027 elections while pursuing cooperation with like-minded parties.
He said Jubilee had previously sacrificed its own interests by withdrawing candidates in some electoral contests to support opposition unity, arguing that coalition politics should not mean the disappearance of individual political parties.
His remarks come as Jubilee struggles to rebuild its influence in Mt Kenya following a series of electoral setbacks, including the embarrassing loss in the Ol Kalou by-election, a seat it previously held.
The rise of DCP has already had casualties.
Former CS Moses Kuria decamped from his own Chama Cha Kazi party in February and registered as an MP aspirant with UDA.
Following the loss in Ol Kalou — where he led the UDA campaigns — Kuria has since announced that he will after all not vie for any political seat.
“You [Gachagua] can have DCP candidates all over Mt Kenya. I will not even vie for any seat myself. But it will end up in tears. Now that you are the undisputed King, cut me the slack and give me some peace. We watch you for the next 12 months,” Kuria said in an X post on July 23.
Political observers say the growing influence of DCP is beginning to reshape the political landscape in Mt Kenya, forcing parties to rethink their strategies ahead of 2027.
Political analyst Kidi Mwaga told the Star that given Kenyan politics remains largely tribal, Gachagua has succeed in building a momentum in the Central Kenya region.
Mwaga added that Gachagua was able to build on the 2022 campaigns in which he mobilised support for Ruto to emerge as the regional kingpin.
“All of them [Central Kenya politicians] must move to Gachagua,” he said.
