Telkor

Telkor is a plane where time moves five times faster than in the normal one. It is also known for its endless wars.

Multiple hostile planes link to Telkor, which means that fiends and angels can access it easily, and other creatures can come through portals as well. The fighting is made more intense because the plane's magic promotes healing. Unless you bleed out quickly or are killed outright, you'll likely heal from most injuries; unfortunately the healing magic doesn't mean you regenerate lost limbs or anything of that nature, not unless you can do so on your own.