Code:
on death:
victim is a player
if damage was caused by void:
if {Hitted::%victim%} is set:
set the death message to "&c&lVOID &c%victim% &7got knocked into the void by &c%{Hitted::%attacker%}%"
delete {Hitted::%victim%}
else if {Hitted::%victim%} is not set:
set the death message to "&c&lVOID &c%victim% &7fell into the void"
on damage:
set {Hitted::%victim%} to true
set {Hitted::%attacker%} to "%attacker%"