Sesshoumaru's character actually a very common and popular antagonist archetype in Japanese fiction, so Verg isn't just "a ripped off Sesshoumaru", it's just that's an example most western fans are probably recognize. The thing is that unlike Sesshoumaru, there was almost no real exploration of his motivations and desires beyond "I want power". Kamiya really never seemed to develop Vergil beyond "mirror to Dante as a foil", and under Itsuno, he was very one dimensional, and Kobayashi has noted at times that he dislikes Vergil. So as the writers intended, he really is that shallow of a character.
In the end in Vergil downfall, Vergil became corrupt instead. So he didn't care to much about his mother. Where as for Vergil in DMC he became like what he was because of his mother's death, and according to Marvel Vs Capcom3 he blamed himself for what happened.
I am from west, but...that doesn't mean i am unaware of everything.
Inuyasha manga debuted in 1996. I assume that japanese designers (Hideki Kamiya) had read Inuyasha.
Then in 2001 DMC 1 was made. And let's assume (because i dont know) that DMC 1 took 2 years to make. Then the start of the project was in 1999, 3 years after Inuyasha debut.
Human mind is like this, we sense something, and our mind records the aspects that made impression on us. What we thought was cool, sad, funny etc. Later when we are in a creative proccess if there is something in our head that we've seen that is relevant to what we want to create we may use it, subconciously or not.
So i assume that Hideki Kamiya read Inuyasha, and his idea for Dante and Vergil came from there. But that he changed it up a bit. I don't look past DMC 1 year for sources of "rip off", i look only back. The ripped off source can't be after the rip off. And i know Sessomaru character type is common, but i looked backwards and Inuyasha was what i found, and it seems to fit what Dante and Vergil was ripped off from. If you know better please enlighten me.
There is also other things to consider when you try to pinpoint if something is ripped off from something else:
1) was the project rushed? less time > more rip off believe me.
Yes, DMC 1 was revamp of what was to be sequal of RE 2.
What happened with DMC 4? They ripped off Bleach - this game was rushed as well. When you have little time your more phrone to ripping off. A rip off guy will think "**** this deadline, ima just steal ideas from this manga i read, and change it up and get finished with this project!".
And the more honesty designer will not have enough time to make a story that's not ripped off partially because it's possible to subconciously rip off things you've seen.
2) Humans don't live that long. Assume that the average age for the game designers who were involved in creation of DMC 1 was 40 years ok? Then you must look through 40 years of story telling from a relevant perspective. For example DMC 1 was serious but not serious like a chinese war story. Therefor you could try checking mangas with such tones to see if DMC 1 has ripped off anything from any manga.
3) And we can assume also that people won't easily remember things that they watched or read ( a movie or story) easily if it was very long time ago. For example you read a book you liked when you were 15. 50 years later, while your trying to make a story of your own, would you recall the story you read when you were 15 clearly? Not very likely i think.
And that is my how i conclude that it MUST BE Inuyasha that is the rip off source of Dante and Vergil. As i said the archetypes means nothing to me, because there are other things than the characters backing up the rip off. Such as the swords they received, by their father, similar to Inuyasha and Sesso father.
. I'm obviously talking about the Marvel Thor and Loki.