Ryuuenjin (龍炎刃, lit. Dragon Flame Blade) is one of Zero's special moves in Marvel vs. Capcom 3. Zero makes use of his saber's elemental mechanics and slices his sword covered in fire upwards in a jumping spiral uppercut. This moves does multiple hits and does not knock down. It acts as Zero's main anti-air special, cementing his "shoutouclone" status with his Hadangeki as his standard projectile.
It also has some frames of invincibility, a staple for many a rising anti-air move (though it is not without recovery that can be punished as Zero falls back to the ground). As a Crossover Counter, this move is fully invincible.
Faster recovery but less distance, hits, height and launching
Middle of the two
|The most distance and height covered and more hits landed, but more recovery|
An iconic Command Art from Mega Man X4, Ryuuenjin is one of Zero's first rising slash attacks and one of his first fire-based/elemental-based moves in general. It can be used to burn wooden objects and deal heavy damage to most well-positioned targets, and dealing multiple hits. Other variations of this move include the E-Blade/Denjin (Electric Blade) from X5, the Shouenzan (Soaring Flame Mountain; a stationary version) in X6, Raijinshou (Raijin/Thunder God Rising) from X7, both the Hyouryuushou (Ice Dragon Rising) and Shouryuuken (Rising Dragon Fist; which references the other Shoryuken) from X8, Tenshouzan (Heaven Rising/Ascension Slash) from Zero 2, Split Heavens/Tenretsujin (Heaven Rending Blade) from Zero 3, and Shouenga (Rising Blaze Fang) from Zero 4. A similar stationary animation applies to Zero's cr.C/Hard Punch in SVC Chaos.
As an anti-air attack, it's mainly used to counter aerial jump-ins and on some occasions in TvC, to finish most air combos, though it can be punished upon falling back down if whiffed or blocked. However, in MVC3 this move no longer has much of a usage due to it no longer being usable in midair (upon its midair version command being replaced by Raikousen). As an assist back in TvC, it was decent in terms of gimmicks used to extend combos with, but this anti-air assist was mainly one reason along with his personality in canon why Zero is often more stronger when played on-point. Also, if used as a Crossover/Variable Counter in TvC, Zero would do a single hit rising slash that would not have any flame effects, which is similar to some of his moves in the Zero series as well as his Rei Shiki Shouryuuzan/Zero Dragon Slash (Zero Style Rising Dragon Slash) in Command Mission.