"Change the player" as in "I want Basil to be the party leader, not Aluxes"? That can be evented.
Changing the ATK stat is a different beast. Default RMXP just sets this value as to whatever your equipped weapon is plus any states that in/decrease the stat. It's not like STR, DEX, INT, or AGL where it increases with level. Nor does it have a method to modify the value like the aforementioned.
But we can make it function similarly:
class Game_Battler
alias add_attack_stat initialize
def initialize
@atk_plus = 0
add_attack_stat
end
def atk=(a)
@atk_plus = a - self.atk + @atk_plus
@atk_plus = [[@atk_plus, -999].max, 999].min
end
def atk
n = base_atk + @atk_plus
for i in @states
n *= $data_states[i].atk_rate / 100.0
end
return Integer(n)
end
end
So now if you do
it should raise Aluxes' ATK stat by 5 permanently.