Danmaku

Overview
Danmaku is a general name for "projectiles", but with a special ring to it. It originates from Gensoukyou, where most people ranging from youkai, humans to gods have a strange aptitude at being able to blast their opponents with a concentrated discharge of spiritual power. It reaches a point that such ability could be considered a certain branch of Magic.

Danmaku Shapes and Powers
Danmaku comes in all sorts of colors and form in Gensoukyou. From the average circular, fireball-like projectiles to the intricate knife and shurikens, the variety spread across a very large spectrum. The greatest question though would be, what determines the shapes and powers of each danmaku?

To answer this, one must go through and analyze how danmaku is usually made. S far, there has been two ways to fire off projectiles that could be considered danmaku. One is rather complicated, the other quite simple, but here are both of them:

Energy Danmaku
Via using one's abilities to control their spiritual reserves. It could be any school of magic, or perhaps, even some martial arts where Qi is released. At any rate, the shape, power, color of the danmaku, everything will depend on the user's control over the medium used. It should also be noted that complex shapes in general, unless they come alongside the spell or technique used will generally be avoided, since the user would waste part of their concentration in thinking of how to uphold the details over the projectiles – nothing but an aesthetic trivial matter, arguably. However, styling danmaku is a privilege of the strong, and a very good way to show off that one has much power, thus, it isn't uncommon for beings on the higher scale of power to add fancy shapes and such to their danmaku. Two good examples would be Marisa Kirisame's star-shaped danmaku and Remilia Scarlet's bat-shaped ones.

Physical Danmaku
Simply throwing whatever weapons one has at the enemy. This kind of danmaku is most common within humans that do not excel in the manipulation of their spiritual reserves, as they will have no need to bother about the shaping and sustaining of the danmaku. All that they'll have to do is... use the weapon as it was intended. Granted, under the strange rules of the spellcard contract, a knife would not necessarily end up bleeding someone to death. Two good examples are any onmyoudo's ofuda talismans such as Reimu Hakurei's and Sakuya Izayoi's throwing knives.

Varrying Lethality
Danmaku can actually kill people, if the output wasn't adjusted enough, or even, left voluntarily high. This is notably common when an extremely powerful being does not watch their step and blast away a much weaker being.. or when they do do that on purpose. This is mostly the case when danmaku is used outside of the spellcards contract, and as a result, end up being regular projectiles.