Secret Area is a web location in MegaMan Battle Network 3. The only way to enter is through a huge hole in the back of the Undernet. NetNavis residing in the Secret Area are particularly strong, including among their numbers such Navis as DarkMan.EXE, YamatoMan.EXE and Serenade.EXE.
The area contains a number of "Monoliths" and “Numbers”. The Monoliths are structures designed to entrap hostile viruses. They can only be shattered by using the “Hammer” item and once broken, the trapped viruses are released. The Numbers are security systems consisting of multiple structures, each with a number, which may be shared with other structures. The only way of defeating them is to simultaneously destroy all structures which share a digit. If a structure is attacked but not destroyed, it retaliates with an instantly killing lightning bolt.