Ryu

Ryu (リュウ) is one of the most iconic and well known characters from the Street Fighter series.

Street Fighter X Mega Man
Ryu is one of the eight bosses. His level style is that of an old Japanese castle. While fighting Ryu, the background is reminiscent of that of Ryu's original arena in Street Fighter II.

Attacks

 * Hadouken (a blue projectile)
 * Shakunetsu Hadouken (Fast)
 * Shoryuken (Dragon Punch)
 * Tatsumaki (Spin Kick)
 * Super Combo: Metsu Hadouken (Extra Large)

Strategy
He is very quick and moves left and right constantly. Charge up the Mega Buster and hit him whenever he stops moving. Usually when he stops he will shoot some Hadoukens, usually three of them. Ryu's Hadouken come in two main varieties: He will shoot a normal Hadouken that goes slow or fast and a yellow Hadouken, called Shakunetsu Hadouken. Ryu has no pattern for attack, so Mega Man must be ready to jump over his Hadoukens. When his volley of Hadoukens is over, he may use the Tatsumaki spin kick across the room, and Mega Man can jump over him or slide under him without taking damage. He will rarely use a Shoryuken. They are easy to dodge as they go up fairly high. This also gives Mega Man an opportunity to get 1 or 2 hits on him. When his Super Combo Gauge is charged, he will shoot a giant purple Hadouken, called the Metsu Hadouken which travels slowly, is harder to break, and more difficult to jump over.

With the Aegis Reflector, stay close to Ryu. Every time he stops, Mega Man should place an Aegis Reflector or two. If he uses Hadouken, they will reflect back at himself. He can also run into an Aegis Reflector and take damage. However, while he is spin kicking, he will pass through unharmed. When he uses the Metsu Hadouken, be sure to reflect it back his way for a little extra damage.

Stage enemies
Note that none of the names are official.
 * Flame Knight
 * Flame Pipi
 * Nurikabe
 * Samurai Joe P
 * Tackle Fire 2

Other appearances
Ryu also appears alongside Mega Man characters in several crossovers, such as the Marvel vs. Capcom series, Namco × Capcom, Project X Zone, Super Smash Bros. for Nintendo 3DS / Wii U (as a DLC character), and Super Smash Bros. Ultimate.

Archie Comics
Ryu is one of the Street Fighter characters present in the Worlds Unite crossover. When he arrives in the merged world alongside Ken, Chun-Li, and Guile as part of the "new Team Sticks", he uses a Hadouken on Vanishing Gungaroo and defeats him with a second Hadouken. Mega Man simply goes "...Huh." Upon seeing the first one. Team Sticks later defeats Magma Dragoon when he attempts to set an Unity Engine in Metro City and in the battle against Sigma's forces.

Trivia

 * Ryu was planned to be a playable character in Mega Man Universe.
 * According to an interview with Seo Zong Hui, Ryu was always planned to be within Street Fighter X Mega Man.
 * In a portion of his stage there is Japanese characters on the wall reading 1987; which is to commemorate the Japanese arcade release of Street Fighter.
 * The Robot Master Hadou Man, from the Secret File parody booklet series of Marvel vs. Capcom: Clash of Super Heroes, is based on Ryu.