Kurama is a four-tailed kitsune; based on this the US dub decided that Kurama was 300, which initially seems sensible (2 tails when he turns 100, 3 when he turns 200, 4 when he turns 300). This, however, doesnât gel with other facts we learn, such as that Kurama hired Genwaku 500 years ago and that he prepared a trap 1,000 years ago.
One creative rationalisation is that Dark Tournament Youko Kurama is actually the way he appeared at 300 years old, explaining why he didnât immediately destroy everyone, given even Younger Toguro was only B-class and his Youko body is later shown to be able to effortlessly destroy mid S-class demons.
Kitsune myth is all over the place, and Kurama seems to be a hodgepodge of them:
Usually, a fox become a kitsune if it lives 100 years; at that point itâs a one-tailed kitsune. It gains another tail each year until at 1,000 years old, as a nine-tailed fox, it turns silver instead of getting another tail. Based on this version, Kurama should be either 400-500 (tails) or over 1,000 (silver).
It seems likely then that YYH runs on the other version of the tails myth - one every thousand years; this would make Kurama 3,000 to 4,000 years old, or 4,000-5,000 if his first 1,000 was silver fur rather than a second tail. We should also note that we have only seen (IIRC) his fox spirit form once, under the influence of the Idunn Box; we donât know how far back it took him, so 4 tails is the minimum he could have.
Based on the thousand-year scale and splitting the difference so he is ânearly 4,000â, when Kurama was born:
The alphabet hadnât been created
The Indus River Valley civilisation was still around
The use of iron wasnât widespread
The events of the Old Testament took place when he was around 1,000
He was around 1,500 when Buddha was alive
He was 2,500 when the nation of Japan was founded (!)
That last point should really impact on fics involving Kurama (and indeed on any fic involving a very ancient character). Assuming the makai doesnât have its own languages (YYH pretty much smoothed over that whole issue), his first language is likely to have been Assyrian, Sumerian, or Old Chinese. Heâs looking at modern civilisation with the perspective that the whole thing has happened in his lifetime, from the nation state to the Internet. He is significantly older than every major religion except Hinduism.
That does make me wonder about the patchy technology in the Makai; to what extent are demons able to learn and adapt to new things? Human neuroplasticity is pretty much unparalleled in nature and allows us to continue learning into adulthood, but we still slow down and have problems learning technology that wasnât common when we were children. One thing that differentiates Kurama from pretty much every other demon we see is that heâs had two childhoods, one in ancient times and one in the modern age. We shouldnât be surprised then if heâs significantly more savvy with ningenkai technology than, say, Yomi.