Navi Shadow

Navi Shadow and Navi Black are enemies encountered in Mega Man Battle Network 4. They are NetNavis that have become tainted by darkness. Both enemies are immune to all attacks (even the Gun del Sol) except for sword-type attacks and Battle Chips.

Navi Shadow
Navi Shadow (abbreviated NavShado in game) are a stronger, faster version of the NormalNavis. They attack with a sword and a cannon.

Navi Black
Navi Black (abbreviated NavBlack in game) are stronger, faster version of the HeelNavis. They attack with a three panel long sword and a cannonball.

In the anime
Three Navi Blacks makes an appearance in episode 23 of Rockman.EXE Stream where they fight MegaMan, GutsMan, and Meddy.