I haven't kept up with Pugs OO (cause cygwin sucks rocks), but can't you create a base class for Person and Monster? Something along the lines of:

class Baseclass {
    has Int $.life is rw;
    has Weapon $.weapon is rw;

    method hit (Int $power) { $.life -= $power; };
    method dead () { $.life <= 0 };
    method attack() { $.weapon.damage }
}

class Monster is Baseclass {
};

class Person is Baseclass {
};
[download]

Where $.weapon is the active weapon and the rest stay in the inventory.

Also, note the variable types. :-)