Talk:Moonlight Arrow/@comment-32614168-20170718142723/@comment-4511886-20170718182855

It is almost certainly the effect of the AR of the bow and Moonlight Arrow combining. Basically, Dark Souls' defence system is built on ratios. This means that the higher your AR, the better your "armor penetration". This is why a weapon with 200 AR will not do double the damage of the same weapon with only 100.

This also means that split damage has a harder time breaking through armor, as each individual damage type is relatively low, and each one has to punch through their opponent's relevant defence value. This means that the Moonlight Arrow will greatly excel with a magical bow, while fire arrows will excel with fire bows, as each individual AR will end up at a higher number. The reason Fire Arrows are better on physical bows is likely either because of the physical damage of the Fire Arrow (as Moonlight Arrows are purely magic damage), or because the enemies you're testing on simply has enough of a gap between their fire and magical defenses to make that difference.