Making a last effort, Charles formed a new army and arrived in the
dead of winter before the walls of Nancy. Having lost many of his
troops through the severe cold, it was with only a few thousand men
that he met the joint forces of the Lorrainers and the Swiss, who had
come to the relief of the town. He himself perished in the fight, his
naked and disfigured body being discovered some days afterward frozen
in the nearby river. Charles' head had been cleft in two by a halberd,
I want to propose Charles "Martin" "The Bold" Duke of Burgundy, who died in 1477 as described above (wikipedia).
There is this famous triple disaster: in the first battle he lost his goods, then his troops, then his (own) blood.
I looked up his life on wikipedia. I think he might qualify because he might be one of the last "real" fighting kings, at the end of an epoch. And he was attacking, not fleeing.
And why they call him bold? (I really wonder)
This Q is interesting. Already Agamemnon had to face some criticism, for letting the other kings do Ares' grim work (sorry). Alexander the Great almost captured Dareios, they say. But in more modern times, after 1500, a king probably does not belong on the battlefield. The business gets too dangerous with cannons and mercenaries. It is always (?) mixed with propaganda when a king puts on uniform.
Achilles to Agamemnon, right at the beginning:
"...though it is my hands that do the better part of the fighting.
When the sharing comes, your share is far the largest, and I,
forsooth, must go back to my ships, take what I can get and be
thankful, when my labour of fighting is done..."
And wiki article Basileus (greek "king")
In Homer the wanax is expected to rule over the other basileis by
consensus rather than by coercion, which is why Achilles proudly and
furiously rebels (the central theme of the Iliad) when he perceives
that Agamemnon is unjustly bossing him around.
Now "wanax" seems to be the mycean "overlord", or "high king", and disappeared as a title. "Basileus" was later used, which before was more "chieftain", (= "tribal chief").
And A.t.G. is mentioned extra:
Basileus and megas basileus were exclusively used by Alexander the Great and his Hellenistic successors in Ptolemaic Egypt, Asia (e.g. the Seleucid Empire, the Kingdom of Pergamon and
non-Greek but Greek-influenced states like the Kingdom of Pontus) and
Macedon. The feminine counterpart is basilissa (queen), meaning
both a queen regnant (such as Cleopatra VII of Egypt) and a queen
consort. It is precisely at this time that the term basileus acquired
a fully royal connotation, in stark contrast with the much less
sophisticated earlier perceptions of kingship within Greece.
(I am asking what is a king, exactly?)