As a further note for real-world edged tools and weapons, I came across an old
book that covers sharpening for practical use. It did not cover swords or
arrows specifically, though it did cover axes, cleavers, chisels, etc. It is
based on the idea that equipment is meant to be used until useless and that the
sharpening is made so the that edge is as close to zero-thickness as possible
with angles met at the edge and those further back of the blade being used to
make it last as long as reasonable as possible until it can be sharpened again
balanced against the "effective cutting length" (basically the effective energy
over a given area at a unit of time given the properties of the material to be
cut and the blade).

Basically (for thrusting and hacking) it recommended for general use to have an
"included angle" of 60 degrees for the edge. This means that with an imaginary
centerline from the edge to the back, the blade is sharpened to a 30 degree
angle on each side.

If the blade is to split a stiff material, then it recommended rounding the area
behind the edge (concave) (generally done with a belt sander) as it minimizes
the friction against the material being cut by having areas contacted between
the blade and the material being cut being at a tangent. This concept is used
in splitting axes (split dried wood). For other material it recommended a
second side angles being ground at 5 degrees less (25 degrees compared to the
edge 30 degrees on each side) starting at about 1/16 inch further back from the
edge. When re-sharpened the edge side angle should be kept at 30 degrees.

For general purpose spikes, spear-like equipment and other thrusting tips, it
recommended the tip being sharpened with an "included angle" of 60 degrees (as
above) with a "rounded bevel" (belt sanding).

A different source says that for fine knives that are meant to cut roots and
vegetable stems, knives should be sharpened with an included angle of 23 degrees
for general cutting and an included angle of 17 degrees for fine slicing. Note
that neither one will hold up against bone or other hard materials. Cleavers
and others that need to go through bone and other hard substances need the
included angle of 60 degrees.

To protect from rust after sharpening or after use and cleaning, the blade can
be lightly coated in flavorless low-acid vegetable or canola oil (and some
mineral oils that protect the blade material and is not corrosive can also be
used) after drying. Olive oil, oils with strong scents, and so forth are
corrosive and should not be used for rust protection.