How can I capture a KO and use that towards a leaderboard?

So I've made it when a player dies their "level" in the leaderboard goes down. How would I make it so if they kill someone it would go up? I've tried playing around with other ko leaderboard scripts but I cant seem to get it to work. Here's my code:

game.Players.PlayerAdded:connect(function(player)
    local leaderstats = Instance.new("Model")
    leaderstats.Name = "leaderstats"
    leaderstats.Parent = player
    local level = Instance.new("IntValue")
    level.Name = "Level"
    level.Value = 0
    level.Parent = leaderstats
end)


game:GetService('Players').PlayerAdded:connect(function(player)
    player.CharacterAdded:connect(function(character)
        character:WaitForChild("Humanoid").Died:connect(function()
            local level = player.leaderstats.Level
            level.Value = level.Value - 1 
        end)
    end)
end)