Blaze Heatnix is one of the eight selectable Reploid bosses from Mega Man X6. Based on the legendary magical phoenix bird, Heatnix was created by Gate to withstand extremely high temperatures in order to explore hot spots beneath the Earth's crust. He would later be reassigned to disaster prevention, but during this time he regularly ignored his coworkers and looked down upon them, viewing them as weak. Because his behaviour resulted in a number of deaths, Heatnix was forcibly retired. He would be resurrected by Gate following the Eurasia Crisis and appointed as one of the Nightmare Investigators.
- Magma Stream: Blaze Heatnix will yell the attack name and, depending on where he is on the screen, purple (non-fatal) magma will fill half the screen. If he's at the top of the screen, it will rise from the ground. If he's at the bottom of the screen, it will descend from the ceiling:
At this phase, as the magma is located under the feet. He will "dive" into the magma and "swim" around in it, and then try to jump up at the character's current position.
- Magma Shot: When he jumps up, he may spit fireballs. Destroy these with any weapon available.
The magma will, however, levitate on the top half of the screen, which is against physics as it's a semi-molten rock. Blaze Heatnix will fly from one side of the screen to the other. Also, drops of lava will fall down continuously at the holes.
- Magma Wave: He will fire crescents either high or low. X and Zero both gain a new ability - the Magma Blade and Shouenzan respectively - which is based on this attack.
- God Bird: He flies off screen, then fly across as a blazing invulnerable phoenix. He can (once again) come either high or low, and from either side of the screen.
Blaze Heatnix is particularly vulnerable to heavy impacts from large objects. He is weak against the Ground Dash weapon that X acquires from Ground Scaravich.
Refined close-quarter weapons are also useful; Zero's Z-Saber can slice through Heatnix's slender frame. Attacks such as the Sentsuizan and Ensuizan are particularly effective.