on death of player:
    if attacker is player:
        if victim is player:
            add 1 to {kill.%attacker%}
            add 1 to {death.%victim%}

command /stats <player>:
    trigger:
        message "&e&l=====&8&l<&cステータス&8&l>&e&l=====" to the player
        message "&9プレイヤー&3:&6 %arg 1%" to the player
        message "&7KILL回数&8:&a %{kill.%arg 1%}%&b回" to the player
        message "&7Death回数&8:&a %{death.%arg 1%}%&b回" to the player
        message "&e&l=====================" to the player