Hello again, this one won't be really long. As it not a very broad concept, but here we are.
Our topic for this rant is the bloodline of heroes, their copies and the inheritors of a spirit. So, without further ado, let's start:
> "I am Cao Cao, the descendant of the famous Cao Cao, Cao Mengde, who was recorded in the Records of the Three Kingdoms. Something like that." --Volume 9, Life 3
> "I belonged to a place called the [Sigurd Institution]. Its purpose was to produce the [True Descendant of Sigurd], someone capable of wielding the Demonic Emperor Sword Gram from among those who had inherited the blood of the hero Sigurd."
> "So, you and Freed…are like siblings or relatives?"
> "Well—, because we were born from multiple genetic patterns, you could call us siblings if you wanted to, and it would also be fine to simply consider us relatives…. By the way, because Freed-aniki and I share almost the exact same genes, you could even say that we're the same person." --Volume 23, Life 3
> "...The Holy Maiden Jeanne d'Arc... It feels complicated to be fighting the one who inherited the spirit of the saint, but I will fight for Michael-sama and everyone! Peace is the most important!" --Volume 9, life 4.
These are 3 statements confirming all 3 existence I just mentioned. Now, we will be talking about them one by one. And we will mention any differences at the end. Here we go:
1-Hero Descandents:
> "I don't know if you know kiddo, but the blood of the hero of this country, [Cao Cao], runs in your body. Well, so far, it's just running in your body, that's all. To be able to awaken that power and use it is a whole different story... And that's up to you." --Volume DX4, Power 2.
So, from this we can infere the fact that while being a Descandent of a hero can bring you some benefits, like better physic, reserves, potential, the bloodline is usually dormant and needs to be awakened to truly tap into its powers. What are those powers? Who knows, certainly not us at the very least.
We do know that they can pass on their talents though. This is shown by Cao Cao inheriting his predecessor's queen eye for distinguishing and unifying talented individuals. Amd George inheriting his predecessor's talent in magic.
Funnily enough, we know 7 natural hero Descandents:
--Cao Cao, Descandent of Cao Cao Mengde of Three Kingdoms.
--Beowulf, Descandent of the original Beowulf, Pawn of Sirzechs Lucifer and stated to be on the top 5 strongest pawns in the Underworld.
--George, Descandent of Jaohann George Faust, the legendary Magician who contacted Mephisto Pheles.
--Arthur and Le Fay Pendragon, Descandents of the Pendragon Noble lineage, from both King Arthur and the witch Morgan Le Fay.
--Marsillio, The descendant of Marsilio Ficino and weilder of the illusion sacred gear, Dreamlike Curse.
--Zhuge Liang, The descendent of the general Zhuge Liang from the threr Kingdoms era. She possesses the Sacred Gear, strategy trap, which allows her to create any trap she chooses such as pitfalls or blocks.
2-Hero Clones:
> "In other words, I'm a test-tube baby. The institute artificially produced Sigurd's descendants."
> "Because someone capable of handling Gram was produced, the institute changed its goal afterwards into something along the lines of 'Let's see how many descendants of the hero Sigurd we can try to make'." --Volume 23 Life 3, part 2.
So for our next entry, the hero Clones, we will be mainly using the Sigurd Clones, as they are the main and only example we have on this phenomenon.
As already established, they are specifically created using IVF( In Vitro Fertilisation), with some modifications added to ensure the characteristics the scientist wanted to be the most prominent A.K.A. be as close to the original as possible.
Now, to be fair, they can still be technically called Hero Descandents, they are just not "natural" ones. We don't really know if that have any effect what so ever.
Fun fact: Sigurd Clones hair isn't naturally white, it just turns like that do to extensive experiments:
> "That man is an Exorcist, a former colleague of Irina and mine. He was a top warrior in the Catholic, Protestant and Orthodox Churches, 'Demonic Emperor Sieg'. He has the same white hair as Freed because they were trained by the same organization. It seems to be the side effect of some kind of experiment..." --Volume 9, Life 3.
For Clones, we know the following individuals:
--Siegfried, wielder of Gram and 4 other demonic swords.
--Freed, basic ass villain and funnily enough, confirmed to be Ishibumi's favourite character in the series.
--Lint Sellzen, wielder of Longinus Incinerate Anthem as of now.
--Sigmund, made from the DNA of Lint, Freed and Siegfried, wants Gram and to be the strongest Demonic swordman ever. Let's hope he don't get lost or smthg like a certain green haired swordman.
--Many other unnamed or irrelevant Clones.
Use Google if you want a basic idea on who they are, although font take all it says as fact.
3-Spirit inheritance:
> "...Hmph, looks like I showed you something unsightly. I, who have inherited the soul of Heracles, is now a kindergarten worker and guard."
> "Same here. Those church people were like 'If you truly are a person who has inherited the soul of Jeanne D'Arc, then shouldn't you aid the people?' and such."
> Perseus. He was the person who had inherited the soul of the Hero of Greece. Just before the Kyoto incident, due to his differing views to Cao Cao, he retired from the group, but apparently, he agreed to help out during the tournament. Even after exiting, there was one time where he went to Cao Cao. The person who brought the Eye of Medusa was none other than Perseus. --Volume DX4, Power 2.
So, as we can see, Spirit inheritors are in fact the least common in DxD. From what we are told so far, we can gather up the following:
--Inheritors of spirits aren't the reincarnation of said spirits. Its more like the spirit got attached to them because of similarities.
--Spirits influence their inheritors, we don't have exact details on how, but we have safely assume it boosts your physical stats and such as if you are a hero Descandent.
--They supposedly influence the mannerism and ambitions of their inheritors, but it is hard to distinguish do to the fact that they tend to be so similar. Now what do I mean by that? This means that they are similar in essence, not in actions. The ones we have in DxD are so opposite to their historical counterparts they are quite similar, like 2 sides of the same coin.
The ones we know so far are:
--Heracles, inheritor of Greek hero spirit, Heracles the son of Zeus.
--Connla, inheritor of the Irish hero spirit, Connla the son of Cú Chulainn.
--Perseus, inheritor of the Greek hero spirit, Perseus, slayer of Medusa.
--Jeanne, inheritor of the Holy Maiden spirit, Jeanne D'Arc of Orleans.
--Momono Kibitsushiko, the inheritor of the soul of Momotarou. Like the original he is accompanied by animal companions such as a Monkey Youkai, a Dog God Youkai and a raven.
I guess that's that, hope that helps clearing up some of the doubts or misconception. See ya next time.
--Side Note: Apparently, after doing some research, I discovered that Perseus is in fact an inheritor AND a Descandent at the same time.
> [As someone who carries the blood and soul of a hero, I would like to challenge other supernatural beings head-on]. His Sacred Gear was a giant shield with a carving of Medusa's face on it — [Aegis Mineralization]. --Volume Shin 3, Life Heroes.
So yeah, that's that.