1. Killing one’s adversary in a duel.
2. Inflicting upon the adversary serious physical injuries.
3. Making combat although no physical injuries have been inflicted.

1. Principals – person who killed or inflicted physical injuries
   upon his adversary, or both combatants in any other cases.
2. Accomplices – as seconds

A duel is a formal or regular combat previously concerted between
2 parties in the presence of 2 or more seconds of lawful age on
each side, who make the selection of arms and fix all the other
conditions of the fight.

If death results, the penalty is the same as that for homicide.

The law disregards intent to kill in a duel

In case of slight physical injuries inflicted on another, penalty
is arresto menor, 3rd paragraph applies only when no physical
injuries are inflicted

There is no such crime nowadays because people hit each other even
without entering into any pre- conceived agreement. This is an
obsolete provision.

If these are not the conditions of the fight, it is not a duel in
the sense contemplated in the Revised Penal Code. It will be a
quarrel and anyone who killed the other will be liable for homicide
or murder, as the case may be