Mega Man X3/Bit, Byte, and Vile

Cutscene
After defeating two Mavericks.

Bit

 * Location: third stage
 * Weakness: Frost Shield (B. Buffalo'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

 * Location: sixth stage
 * Weakness: Tornado Fang (T. Rhino'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

 * 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), Ray Splasher (N. Tiger's)

If you defeat him with the weapons stated here, he will not reappear as boss of the second final stage. A different boss will be there, instead of him.