Child Emperor vs. Phoenix Man

It's good to have ambitions, but someone truly remarkable wouldn't have joined the Monster Association in the first place.

Child Emperor vs. Phoenix Man was the first battle between the S-Class hero Child Emperor and the Demon-level Mysterious Being Phoenix Man.

Prelude
Child Emperor is leaving a room after extracting some data about the Monster Association Headquarters. As Child Emperor leaves the room, he takes out a large lollipop to relieve the built-up stress, but when he looks up, he sees Phoenix Man in front of him, his Mini Octotank No. 8 broken underneath the monster's feet.

Battle
Phoenix Man mocks Child Emperor and the childish design of his machine, sarcastically asking him if he thought he came here to play. He continues by saying that he envied Child Emperor's youth and carefree life, but that he would nonetheless not hold anything back. Child Emperor chews his lollipop into shards and asks him if he was a simple cadre, to which Phoenix Man replies by saying he was more like middle management and he was ranked higher than most around him. Phoenix Man goes on a rant by saying how the Hero Association is marred with politics and that Child Emperor was only S-Class because he was "slightly smarter" than average, also remarking that the hero shouldn't take the praises of adults seriously. He continues by stating the Monster Association was merely a stepping stone for him, and that eventually, he would take the title of "Monster King" from Orochi. Shifting his tone to a yelling voice, he arrogantly says his name and explains that he was once a human who wore a bird costume but could not take it off, and eventually he fused with the costume, officially becoming a monster. Phoenix Man proclaims that this is where Child Emperor would die, yet he would give him an instant, painless death, saying it was the least he could do, and strikes with his Beak Attack. Alas, the monster's attack is blocked by an invisible wall. Child Emperor reveals that while he was monologuing, he set up an invisible wall with film that was extremely resistant against the force of sudden impact. According to him, it could even be rolled into a tube or used as a candy wrapper, yet it was still in the testing phase. He continues by explaining that he was originally going to capture him alive and have him lead the way, but since he is in a bad mood, he'd kill him right then and there. Suddenly, an array of very sharp and lethal weaponry shoots out from Child Emperor's backpack and strikes Phoenix Man at speeds he can't dodge or defend. In an instant, he is torn apart by this weaponry and drops down dead. As Child Emperor stands over his corpse, he remarks that it is good to have ambitions, but someone truly remarkable wouldn't have joined the Monster Association, yet he considers that this would also apply to himself. With that, he notes that his fight with Phoenix Man managed to cool him down a bit and he turns around, making his way towards Waganma.

Aftermath
Child Emperor manages to save Waganma from his jail cell after defeating some more monsters and starts making his way out of the Monster Association Headquarters with him. They then run back into Phoenix Man's corpse, when Phoenix Man suddenly resurrects thanks to his costume.