Crimson Viper

Crimson Viper (クリムゾン・ヴァイパー), also known as Maya (マヤ) is a video game character from the Street Fighter series who made her debut in Street Fighter IV as part of the starting lineup. Though employed by S.I.N., in reality, Crimson Viper is a secret agent under the employ of a U.S. government agency, later shown to be the CIA.

Street Fighter X Mega Man
She is one of the eight bosses that appear in Street Fighter X Mega Man. Her weakness is the Lightning Kick.

Attacks

 * Impulse (a ramming-type attack)
 * Seismic Hammer (an area of effect attack)
 * Burning Kick (a jumping fire attack)
 * Optic Laser (a laser attack)
 * Super Combo: Burning Dance (a ramming attack followed up by a large area of effect attack)

Strategy
She is pretty fast and will constantly use her Burning Kick, sometimes she will use this attack consecutive times, if she is close to the wall where Mega Man is standing, a slide will make him get out of that spot before she lands a hit with her kicks. She also uses her Impulse quite often, although it's a little easier to predict, once she starts glowing yellow, a well timed jump will avoid the attack. She will also use the Optic Laser, using the Mega Buster is useless since it takes too many hits to destroy the projectile and it travels fast on the screen. Again, jumping is the best option. Her Seismic Hammer will make the ground below Mega Man explode with shockwaves, sometimes she will use it once and sometimes up to 4 times. All of these attacks require jumping, so once she does a Burning Kick, it will throw off most people while fighting against her. When her Super Combo Gauge is charged, she will attack with her Burning Dance, which starts off as a ramming attack followed up by an explosion in the middle similar to those of her Seismic Hammer but bigger.

With the Lightning Kick, it's recommended to attack once she is getting close to Mega Man, rather than Mega Man going close to C. Viper, since she could attack with her Burning Kick at any time. Land a few strikes, then back off until a new attack opportunity shows off.

Stage enemies
Note that none of the names are official.
 * New Screw Bomber
 * Laser Joe
 * Giant Screw Bomber
 * Uni Skull
 * Industrial Spine

Other appearances
C.Viper also appears alongside Mega Man characters in Marvel vs. Capcom 3