Raidou Kuzunoha VS King Abaddon/WMG

Lucifer / Louis Cypher is the very first "Spark"

 * He mentions the word "Spark" a lot when talking to others.
 * He may not be a Mad Scientist, but he happens to be one of the Chessmasters of the Shin Megami Tensei series.

Raidou and the other Kuzunohas are descendants of Abe-No-Seimei/ the Kitsune Kuzunoha

 * Mikaboshi called Raidou a Fox, and well the devil summoner a 'clan of foxes'. And there is a 'Nameless Shrine' attached to the Kuzunoha legend. Having a supernatural being as an ancestor can explain why Raidou has his special abilities.

Raidou is the first in a long line of detectives, warriors and all around geniuses
Raidou being a reasonably attractive male would theoretically have no problem reproducing, This being Shin Megami Tensei I think it's safe to say he did. However when someone as awesome as Raidou reproduces...well you know what they say.

Therefore it's not to much of a stretch to say that many SMT characters and characters from other series as well, could all be decended from Mr. Kuzunoha.

These include but are not limited to.

Naoto Shirogane, Arisato Minato, Benjamin L Lawlett, Ed, Shawn Spencer, Robert Goren, Solid Snake, and Travis, Henry and Jeane

It would be quite possible for Raidou to be an ancestor of Naoto, in fact it's somewhat impied, and since Fanon says that Minato and Naoto are related it's a simple use of the transitive property to say he would be the Ancestor of Minato as well.

As for L, well he's a great detective and despite one massive freak out takes the exsistence of Shinigami fairly well implying he may have some subconscious familiarity with the surreal. Both of these traits he would have inherited from Raidou. As for Ed, well a small group of fans have specualted that Ed and L are related, so the transitive property from above also applies.

For Robert and Shawn there is the fact that both are incredibly astute detectives and the later mentioned may or may not be a psychic. Now if the problem of two red blooded american boys being descended from a Demon Hunting Ninja strikes you as odd just remember there was at least one female american who came into contact with Raidou, and Raidou being a SMT Protagonist, it wouldn't be to much of stretch to say the least.

With Snake it's equally justifiable in that one of his biological mothers (yes plural) was Japanese. Snake has a knack for Fire Arms to say the least and is rather quite astute both traits once again could have been inherited from his Kuzunoha ancestry.

As for Travis, Henry and Jeane, their nationality is ambiguous enough and in a universe like No More Heroes you don't need much justification for Wild Mass Guessing.

And while were on the subject, I suppose it's worth noting Dante and Virgil of DMC fame may be a Kuzunoha descendent as well, Dante and Virgil are both sons of Sparda, a demon who "Awakened to Justice" now this may be entering on squick but being Devil Summoner Raidou has many female demons at his beckon call and the idea of him hooking up with any one of them is lampshaded to say the least. Now Sparda could be the byproduct of one of Raidou's Demon conquests, and his human blood is what caused him to "Awaken to Justice". This would make Sparda and both of his sons Kuzunoha Descendants as well.

(This theory is complete crack.)

Gouto's crime was becoming immortal/extending his lifespan.

 * Gouto notes that "Raidou Kuzunoha" has existed for ~1000 years, which on average would leaves each of the 13 previous Raidou to live an average of just under 77 years. Even assuming they all got their title at 17, that requires everyone of them to be in their 90s pre-modern medicine (even then, 90+ people aren't exactly in a condition to fight demons). Making him immortal as a punishment is a karmatic joke.

Shinado is Philemon/Nyarlathotep.

 * Shinado seems to be a dual existence, just like Philemon and Nyarlathotep are: two facades of the same... thing. One side of Shinado has hope in mankind (like Phil), the other wants to destroy it (like Nyar).
 * Both Shinado and Philemon use cool looking masks.

In the end of the first Raidou game it was Yatagarasu that rested on Raidou shoulder as he went to his next mission not Gouto.

 * Yagataratsu is described as a raven in Japanese mythology and in this game so it would not be too much of a stretch to say that Yatagarasu came to Raidou personally to congratulate him on a job well done.