Mega Man X3/Bit, Byte, and Vile

Cutscene
After defeating two Mavericks.

Bit

 * Original name: Vajurila FF
 * Location: third stage
 * Weakness: Frost Shield (B. Buffalo's) or Triad Thunder (V. Catfish's)

If you defeat both him and Byte with the weapons stated here, they will not reappear as boss of the first final stage. A different boss will be there, instead of them.

Byte

 * Original name: Mandarela BB
 * Location: sixth stage
 * Weakness: Tornado Fang (T. Rhino's) or Frost Shield (B. Buffalo's)

If you defeat both him and Bit with the weapons stated here, they will not reappear as boss of the first final stage. A different boss will be there, instead of them.

Vile

 * Original name: Vava
 * Location: teleport hatch hidden in three stages: B. Buffalo's, V. Catfish's and C. Crawfish's;
 * The hatches disappear if you defeat all eight Mavericks.
 * Weakness: Spinning Blade (C. Crawfish's) or Ray Splasher (N. Tiger's)

If you defeat him with the weapons stated here (at least the final blow), he will not reappear as mini-boss of the second final stage. A different boss will be there, instead of him, and you can then obtain Zero's Saber.