  This paper studies quantum symmetric pairs $(\widetilde{\mathbf U},
\widetilde{{\mathbf U}}^\imath )$ associated with quasi-split Satake diagrams
of affine type $A_{2r-1}, D_r, E_{6}$ with a nontrivial diagram involution
fixing the affine simple node. Various real and imaginary root vectors for the
universal $\imath$quantum groups $\widetilde{{\mathbf U}}^\imath$ are
constructed with the help of the relative braid group action, and they are used
to construct affine rank one subalgebras of $\widetilde{{\mathbf U}}^\imath$.
We then establish relations among real and imaginary root vectors in different
affine rank one subalgebras and use them to give a Drinfeld type presentation
of $\widetilde{{\mathbf U}}^\imath$.
