invisibility killing

say someone with the username "smartduck45" killed someone with the username "flameboy67" with a sword while smartduck45 had the invisibility effect then the death message in chat would be "flameboy67 was slain by smartduck45" but you could make it so that the death message was "flameboy67 was slain by invisibly player" with the "invisibly player" bit being in bold or italics to show that it is not there username, and same for if someone invisible is killed (invisibly player was slain by <player name>) and if smartduck45 killed a player using a mace while he had invisibility then it could say "<player name> was smashed by invisible player" and all the other different death messages could be changed when a player has invisibility whether the player being killed or doing the killing is invisible