How to add a tagging system to this sword script?

I have tried everything I could find about creator tags and I just can't seem to find a way to fit it in this script. Some help would be appreciated!

local TOOL = script.Parent
local BLADE = TOOL.Blade
local ANIMS = {}
for index, CHILD in pairs(script:GetChildren()) do
	if CHILD.Name == "Slash" then
		table.insert(ANIMS,CHILD)
	end
end
local FIGHT = false
local FRIENDLYFIRE = TOOL.FriendlyFire
local IDLEANIM = nil
local TRAIL = BLADE.Trail

function Slash()
	if FIGHT == false then
		local HUM = TOOL.Parent:FindFirstChildOfClass("Humanoid")
		if HUM then
			TOOL.Slashing.Value = true
			BLADE.Swing.Pitch = math.random(8,12)/10
			BLADE.Swing:Play()
			TRAIL.Enabled = true
			local SHOUT = script.Grunt:Clone()
			SHOUT.Parent = HUM.Torso
			SHOUT:Play()
			SHOUT.Pitch = math.random(8,12)/10
			game:GetService("Debris"):AddItem(SHOUT,2)
			local BOD = Instance.new("BodyPosition",HUM.Torso)
			BOD.Position = HUM.Torso.CFrame * CFrame.new(0,0,-6).p
			BOD.P = 750
			BOD.D = 35
			BOD.MaxForce = BOD.MaxForce*25
			local ANIM = HUM:LoadAnimation(ANIMS[math.random(1,#ANIMS)])
			ANIM:Play()
			FIGHT = true
			local HIT = BLADE.Touched:Connect(function(TOUCHED)
				if TOUCHED.Parent:FindFirstChildOfClass("Humanoid") then
					local HUM = TOUCHED.Parent:FindFirstChildOfClass("Humanoid")
					local PASS = true
					if game.Players:FindFirstChild(HUM.Parent.Name) and FRIENDLYFIRE.Value == false and TOUCHED.Parent:FindFirstChildOfClass("ForceField") == nil then
						PASS = false
					end
					if PASS == true then
						HUM:TakeDamage(TOOL.Damage.Value)
					end
				end
			end)
			ANIM.Stopped:Connect(function()
				TOOL.Slashing.Value = false
				BOD:Remove()
				TRAIL.Enabled = false
				HIT:Disconnect()
				wait()
				FIGHT = false
			end)
		end
	end
end

TOOL.Activated:Connect(function()
	Slash()
end)

TOOL.Equipped:Connect(function()
	local HUM = TOOL.Parent:FindFirstChildOfClass("Humanoid")
	if HUM and script:FindFirstChild("Idle") then
		IDLEANIM = HUM:LoadAnimation(script.Idle)
		IDLEANIM:Play()
	end
end)
TOOL.Unequipped:Connect(function()
	if IDLEANIM then
		IDLEANIM:Stop()
	end
end)

You can check beforehand if the target is alive and will die with the damage you are going to deal, then apply the code you want.

You can also create an objectvalue to the player who took damage with a value of the player that dealt it. Then use a Humanoid.Died event to check if there is such objectvalue to apply what you want. Remember to make these objectvalues destroy after some time, so it wont stack and count players who dealt damage a long time ago.

This last option is better to use when you want to check if multiple players dealt damage at the time, for things such as share exp on RPGs or just count kill score for more than one player.