\documentclass{article}
\usepackage{lltjext}
\usepackage{luatexja-fontspec}
\setmainjfont{IPAmjMincho}
\setmainfont{Crimson}
\begin{document}
abc𛀐𛀑𛀒𛀓𛀔𛀕𛀖𛀗𛀘𛀙𛀚𛀛𛀜𛀝𛀞𛀟\\
abc𛀙゙「𛀬゙𛀰゙」𛀸゙𛀿゙𛁅゙𛁈゙𛁛\\
abc𛀙゙「𛀬゙𛀰゙」𛀸゙𛀿゙𛁅゙𛁈゙𛁛\\
abc𛂞゚𛂟゚𛂠゚𛂡゚𛂢゚𛂣゚𛂤゚𛂥゚𛂦゚𛂧゚𛂨゚\\
This Latin text should be rendered in crimson.

\parbox<t>{20\zw}{%
abc𛀐𛀑𛀒𛀓𛀔𛀕𛀖𛀗𛀘𛀙𛀚𛀛𛀜𛀝𛀞𛀟\\
abc𛀙゙「𛀬゙𛀰゙」𛀸゙𛀿゙𛁅゙𛁈゙𛁛\\
abc𛀙゙「𛀬゙𛀰゙」𛀸゙𛀿゙𛁅゙𛁈゙𛁛\\
abc𛂞゚𛂟゚𛂠゚𛂡゚𛂢゚𛂣゚𛂤゚𛂥゚𛂦゚𛂧゚𛂨゚\\
This Latin text should be rendered in crimson.
}

\end{document}




