[@KawaiiKyouko] I just thought of this, but I think Rider's bow and arrow NP may need some minor adjustment, as the multiplication effect is predicated on what are strictly speaking human limitations i.e. multiplying every .1 seconds at a velocity of 100 m/s. The arrows won't multiply nearly as much if the projectile is traveling at speeds vastly greater than that, and as we've seen before, Servants tend to get a bit ridiculous when it comes to feats of superhuman strength and weapons mastery.

For example, EMIYA, who is a relatively weak Servant excluding Unlimited Blade Works, is capable of firing arrows at a target many, many kilometers away at speeds vastly exceeding that of sound. Granted, he can only fire accurately at those distances thanks to Clairvoyance, but we're more concerned with the arrow's kinetic energy and velocity here, since Khan's NP is basically a carpet bombing. Observe:

[youtube]https://www.youtube.com/watch?v=GfTGkrSSpZA[/youtube]

Archer's arrow took about 8 seconds to make all the way across at least half of Fuyuki, and his strength (thus draw weight) is only a measly D, which is vastly outstripped by Genghis here. At the speeds Genghis' arrows are likely to be traveling, their replication will be greatly nerfed if they can only double once every .1 seconds. Might I suggest making it so that they double based on distance, or by how many horses Khan has summoned?