How they compare: Mikeru (Mermaid Melody Pichi Pichi Pitch)

WARNING: Spoilers for Mermaid Melody Pichi Pichi Pitch 

Long ago the world was ruled by a different species of ancient beings that resembled angels. When the new sentient species, humans, emerged, the ancients; their hearts filled with mercy for the newly born species left this world for the world of dreams, to give this new species a world to call their own. 

However a weak member of their kind known as Fuku did not follow. Instead Fuku watched in resentment at the development of human society until the modern day where he used the cloning technology of man to create a clone of the long-dead Emperor of the Ancients Mikeru. Fuku manipulated the clone, stelling him his rebirth was because the gods appointed him to rid the Earth of humanity who were so spoiling it and to bring about the return of the ancients.

The clone of Mikeru, thinking himself the original Mikeru believed him, and despite his gentle heart, began to seek righteous vengeance on the world of man and the restoration of "his" ancient empire.

Mermaid Melody feats can be hard to interpret, due to the way many statements that would be really good feats are stated to make it unclear whether they are meant to be literal or figurative (statements such as destroying a kingdom, illuminating a sea etc.). This is not helped by a number of seeming low-end showings, such as how Gaito, the final villain of the first half destroying his own castle was seen as an impressive showing. However I believe there is enough support to suggest the verse is a lot stronger then it seems and indeed even stronger then I thought.

Even in the first chapter the villain Izuru could create a storm with her own power yet mermaid form Lucia can survive this power and indeed calm the storm with her singing. There are several other large storm feats for even low tiers, including Izuru being claimed to be able to create a storm that can drown an entire city. If indeed this is literal it would take very likely gigatons of energy to be able to perform, and at the very least these storm feats are consistently in the kiloton to megaton range of energy. The High Tiers, would be much stronger, especially Mikeru who was described as a "transcedent power" beyond the verse normally. 

The Indian Ocean Princess Sara with her power was capable of accidentally destroying her own kingdom across the indian ocean, creating waves capable of sinking large ships on the water's surface while deep underwater and creating tsunami. The Indian Ocean stretches larger then Europe or Oceania meaning a feat of this magnitude was likely in the teraton to even petaton range, consistent with the Mermaid Princess pearls being said on page 1 to exist to illuminate the oceans. Sara also claimed that she would fill the world with the dark sea. This statement isn't explained very much, but even conservative assumptions would likely be in the multi-continental range. Mikeru's dream world size is also of note as Mikeru's plan was to fuse it with the human world. Assuming the "human world" is at least the size of where humans inhabit, this would be at least a multi-continent feat. It also seems at points Mikeru's dream dimension contains stars, though it's a bit hard to tell with the art and obviously that's a very high end interpretation, arguably an outlier. Beyond that the power of Aqua Regina, the Goddess of the Oceans was able to make the dream dimension shimmer in and out of existence. This is notable because Mikeru was able to rival the power of the 7 Mermaid Pearls which is the power of Aqua Regina. 

A quick note: While Gaito's destruction of his castle was seen as a sign of his power, it was not because he could destroy a building, but because it was being destroyed without him acting on it, or as he put it "this building can not contain my power" showing that just his presence was destroying the building. Just before all this, Gaito was able to casually telekinetically lift his castle above the waves.

In terms of speeds, a nameless Mermaid gave birth to twin sisters Noel and Karen on "opposite sides of the Earth" in the Arctic Ocean and the Antarctic Oceans, the twin sisters being the princesses of those kingdoms. While the biology of mermaids isn't explored much the average birthtime for humans between twins is 17 minutes would require easily double digit mach speed, and given the circumstances, very likely MHS speed. This is consistent with the Mermaids being able to casually swim into other oceans, and with Gaito's invasion between mermaid kingdoms happening so quickly that the mermaids didn't know what was going on despite communication between them. Mikeru should easily scale above these things.

So overall Mikeru should be likely Multi-Continental and Hypersonic, possibly Massively Hypersonic. This is consistent, possibly even a low-end as afterwards Lucia was stated to have protected the "Survival of the planet" from Mikeru, suggesting that his attempt to overlay his dream reality on Earth was a multi-continent to planetary feat. 

As an ancient one, Mikeru can inhabit dreams, and move back and forth between them and reality, to the point that to him, dreams are the true reality and reality merely a dream. Mikeru can also fly and teleport at will. The ancient beings are also noted to be able to sense the warmth of all living beings. He channels his power into lightning strikes on his enemies symbolic of divine retribution. 

Mikeru's most famous ability is his absorbtion. Mikeru's wings can absorb beings into him, granting him their powers. He can also cause that being to appear in his wings to use as a defense if his opponent is unwilling to hurt someone he has absorbed. Mikeru can also absorb memories into his wings.

Mikeru has other mental abilities. He can read minds as he did to Michal and he can create emotions in others, just as he created love in her for Kaito so as to manipulate her. It was also noted if he succeeded in his goal he could control "every thought in every heart" suggesting that within his own dimension he has planetary scale brainwashing. He can also astral project his soul into the waking world or project an actual physical body in the living world should it serve his aim. 

Mikeru can also bestow powers, as he did onto his followers the winged ones, and he can take powers as he suggested he might do with Lucia. He also was able to transmute his followers, since after Gaito transmuted the Black Beauty sisters back into their original forms (anglerfish) for betraying him, Mikeru found them and restored their forms as Black Beauty sisters. This is also likely a sensory feat for him, since it he would have needed to know which anglerfish were the Black Beauty sisters.

In his own dimension, Mikeru has reality-warping, able to even fuse his whole dream world with the Earth, including the summoning of giant monstrosities into the Earth that he implied could potentially stop the Mermaid Princesses.

After breaking the will of the panthalassa girl Michal, Mikeru absorbed her and presumably gained the psychic abilities of the panthalassa abilities. While he has superior dream abilities, this would likely give him some level of telekinesis (Gaito could telekinetically lift his entire castle), the ability to manipulate his own memories (Kaito sealed away his own memories so that Mikeru could not steal them), as well as some level of enhanced recovery (Panthalassa children were noted to recover from injury and sickness at a superhuman rate), being able to manipulate water and project light from their foreheads.

However Mikeru has notable weaknesses. His connection to his body seems to be unstable, and his physical body is a lot more fragile then his level of power would seem to suggest. This seems partially related to his nature as a clone (and strangely, affecting the original body of Mikeru frozen in ice is suggested to affect Mikeru), and partially due to his mindset. Near the end of the story, Mikeru suffers from a psychological breakdown upon realizing that he was not a perfect being delivering righteous justice but instead a construct made by human technology who has no more right to the world then they do. Originally, his gentle heart made him not want to hurt the beautiful and the good and so he tried to spare the Mermaid Princesses and offered for them to join him, but the revelation that he was not the wraith of Heaven sent upon humanity, but a wisp of an ancient era given life by humanity themselves, caused him to psychologically break down and allowed the soft song of the Mermaid Princesses to reach him.

Name: Mikeru

Origin: Mermaid Melody Pichi Pichi Pitch

Classification: Ancient entity

Powers and abilities: Mental existence, can go back and forth between dreams and reality, flight, teleportation, elemental manipulation (lightning, water, light), weather manipulation, absorption (physical, memories, powers), power-bestowal, reality-warping/dimension manipulation (multi-continental), mental manipulation (planetary), transmutation, mind-reading, enhanced senses (can sense the warmth of all life), telekinesis, astral/physical projection, limited sealing (can seal away his own memories), regen (low)

Weaknesses: Affecting the body of the original Mikeru can disrupt him, psychologically instable and unfocused near the end of the story, does not want to hurt the good and the beautiful, weaker outside dreams

Destructive Capacity: At least multi-continental (Planned to override the human world with his own dream world, far superior to Sara who could flood the world with the dark sea), possibly planetary (was considered a threat to the survival of the planet)

Range: Planetary 

Speed: At least hypersonic, likely massively hypersonic

Durability: At least multi-continental (even when unfocused, required all 7 Mermaids to overpower him, most of whom should be relative to Sara)

Stamina: Unknown

Standard Equipment: Nothing notable

Intelligence: A good manipulator (manipulated Michal into allowing herself to be absorbed)

So how well would he do in other verses?

In DC Comics, Mikeru would do quite well for his tier, especially give how strong DC is in general. He would be at the relative top of his rough power "tier" given his nigh-planetary stats though his speed would be relatively low only about as fast as the faster normal humans like Batman and Deathstroke who scale to hypersonic feats. Against most people in his tier, and indeed even against much stronger people if he's punching up, his mental existence would make him difficult for the verse to deal with, especially if he's growing stronger by absorbing entities. His planetary scale mind hax would also be nigh-unrivaled on the main DC Earth with only the absolute top tier psychics being able to deal with that or being able to fight Mikeru in the dream world at all.

It's possible he could be much more dangerous if he acts subtly and absorbs beings to expotentially boost his own number of powers. I actually considered him for the DC-verse Strategy Guide, however the big problem is Aquaman in particular absolutely hard counters Mikeru. While Mikeru is more powerful, Aquaman is a lightning-timer meaning he could dodge Mikeru's fastest attack, his telepathy is strong enough to counter Mikeru's, and even if Mikeru tries to bring him to the dream dimension, Aquaman can simply counter by bringing him into the spiritual sea which would immediatly break Mikeru's mind by showing him his own corruption. Also if Mikeru tries to absorb him, Aquaman's magic-negating hand could negate a number of Mikeru's abilities and potentially keep him from getting absorbed.

So overall, Mikeru would do really well, surprisingly well actually, and could even punch above his weight class and beat Kryptonian Level entities. The main problem is that Aquaman is an ideal hard counter.

 

In Marvel Comics, Mikeru would be classified as a High Meta Level entity. Mikeru similar to DC could be a pretty big threat given the sheer number of superpowers he could absorb and he has a pretty good matchup on most of Marvel's High Metas to Low Heralds. That said he's overall less of a threat then he would be in DC due to Marvel's sheer number and potency of psychics.

Mikeru would still be a strong threat and would likely be considered a high tier psychic, though not a top tier. Marvel Psychics often scale to the planetary level mind hax, and actually practice fighting in dreams to train. Any really high tier psychic like Emma Frost, Jean Grey, etc. would be able to give Mikeru a run for his money, and teamwork between a number of them should be able to shut him down. 

While Mikeru's other abilities might be tricky, it should be noted that his own mind has basically no defenses against mind attacks except pre-emptive strike, and in fact is arguably more vulnerable then normal given his instability.

 

In the Lovecraft Mythos, another series about hidden powers beneath the waves, and which deals heavily with dream symbolism albeit opposite in tone to MMPPP, Mikeru would be beyond the comprension of general beings of the universe like the mi-go or the elder things and would be roughly great old one tier, similar to Cthulhu who scales greatly above his son whose fingertips were the size of mountains, though with better raw power feats outside of Cthulhu's arguable stellar feat. Mikeru's mind manipulation would be similar to Cthulhu, albeit possibly a bit stronger as Cthulhu's didn't affect those with more rational minds. He would be much slower however. 

Overall Mikeru would be comfortably in the lower Great Old One Tier around the strength of Cthulhu. He could defeat most "normal" alien races, but the stronger forces of the universe, let alone the greater existence then the universe are outside his control. With his dream powers he could likely control a good portion of a single universe.

In Neon Genesis Evangelion which also involves a battle against strange "angels" that are related to a prehistoric sentient species that walked the Earth before man, though again with a very different tone, Mikeru would be very strong though probably not capable of solo-ing the verse. 

While most Angels would not be comparable in power to the power of Mikeru, the strongest ones like Adam whose power created massively hypersonic shockwaves that annihilated the continent of Antarctica and erased all living entities in the Southern Hemisphere down to bacteria which would put him comparable in power and speed to Mikeru. Adam probably wouldn't be able to hit Mikeru given Mikeru exists in the dream reality, even with the A.T. fields soul hax, that said Lilith should be able to win with her form of A.T. field which is based in the willpower of beings and can affect the mental plane, and should likely even be effective against Mikeru, given at the end of his series his will had corruded by the realization that he was not a superior being to humans. 

The writer of MMPPP did do some of the anime composition for xxxHolic and MMPPP was published in the same magazine and was published in the west by the same company as xxxHolic and Tsubasa Resevoir Chronicles. In the Clamp Multiverse, statwise Mikeru would be above the general magicians and wizards and spirits but below the likes of the Rune Gods of Cephiro in terms of speed and only potentially able to somewhat keep up with them in power.

That said Mikeru's dream hax would be really strong in Clamp, as has been shown in X/1999 and Mikeru has a lot better dream hax then anyone in the Clamp verse save for god tiers. For the most part only the great magicians and most powerful spirits and gods would be able to beat Mikeru via sealing or being able to attack on the spiritual plane.

Mikeru would be a massive threat to most planets in the Clamp world and would require the intervention of one of the strongest magic-users or one of the gods to stop. Though it should be noted that the Pillar and the Dark Pillar of Cephiro would likely be able to affect Mikeru as seen when Nova was able to enter Hikaru's dreams as well as the sheer preponderance of godly level willpower and reality-warping resistance in the Cephiro system.