Spider

Spider (スパイダー) was introduced as an ally in Mega Man X: Command Mission. He uses playing cards as weapons and has a high rate of evasion. He apparently was somewhat well-known in Giga City before the game took place, as at least one resident seems to know him.

Spider first appears in Chapter Two, when he is hired by Wild Jango to seek out and assassinate X. When he finds X, he engages him in combat but is defeated. Not to be deterred, he returns not long after for a second strike, this time easily getting the upper hand. However, upon seeing the crest of his former comrade Aile in X's possession, he decides to join X and fight against his employer instead of for him. He stays with the party until X and the others are trapped by Incentas, when Spider "sacrifices himself" to allow the others escape.

In truth, the real Spider was murdered by Redips shortly after he joined X (most likely after they succeeded in rescuing Professor Gaudile and Cinnamon, as X commented on Spider's long absence as soon as he entered.). Redips, using his Chameleon Chip, was able to assume the form of Spider afterwards, and accompanied X and his allies until his apparent sacrifice, at which point he begins to make his movements towards acquiring the Supra-Force Metal.

Spider, like Axl, has a Chameleon Chip, and can assume multiple forms. This is how he carries on the masquarade of the Maverick Hunter Colonel Redips, who was placed in charge of the Gigantis Island unit.

In the final chapter, he reveals himself as being both Spider and Redips. By then, he has obtained the Supra-Force Metal from X, and uses it to take on an entirely new form.

Trivia

 * It seems as if the two forms have separate personalities, as although both are evil (or at least, Redips' portrayal of him, as it's hinted that the real spider might have joined the protagonists and was killed off-screen by Redips), Spider is clever and suave while Redips is insane and power-obsessed. Of course, this is mere speculation and cannot be confirmed.
 * Whether or not Spider really knew Aile, or he simply fabricated the story to justify his joining X is unknown, as later, Spider would betray his comrades to fulfill his own goals. On the other hand, assuming that the Spider that fought Wild Jango was the real spider (as it was implied that Spider had to have existed beforehand, due to Redips' copy ability.), and he was killed sometime after the rescue mission of Professor Gaudile and Cinnamon, it's entirely possible that he really knew Aile.
 * Redips is Spider spelled backwards.
 * Interestingly, despite the fact that Spider/Redips was the one who murdered Botos in Chapter 8, he doesn't mimic him in chapter 10 as he did with the other Rebellion army members.