Further details of the behavior of a fault with a fluid-filled region are presented: an oblique fault is modeled by an interface across which two elastic bodies are in frictional contact and the tectonic stresses varying linearly with respect to depth are taken into account. It is shown that a fault can keep fluid if there exists a spatially fluctuating tectonic stress field superimposed on the linear depth-dependent stress field, although the fluctuation amplitude must be larger than a lower limit when the fault is oblique. It is also revealed that except for the case of a horizontal fault, there is an upper limit for the size of the fluid-filled region even if the fluctuating stress field is spatially periodic. As the fluid-filled region is created, slip spreads simultaneously along the fault. This resulting slip is also analyzed.