  In an axiverse with numerous axions, the cosmological moduli problem poses a
significant challenge because the abundance of axions can easily exceed that of
dark matter. The well-established stochastic axion scenario offers a simple
solution, relying on relatively low-scale inflation. However, axions are
typically subject to mixing due to mass and kinetic terms, which can influence
the solution using stochastic dynamics. Focusing on the fact that the QCD axion
has a temperature-dependent mass, unlike other axions, we investigate the
dynamics of the QCD axion and another axion with mixing. We find that the QCD
axion abundance is significantly enhanced and becomes larger than that of the
other axion for a certain range of parameters. This enhancement widens the
parameter regions accounting for dark matter. In addition, we also find a
parameter region in which both axions have enhanced abundances of the same
order, which result in multi-component dark matter.
