Why can't I access the Player in a module script from this setup?

When a player presses a key, it fires an event. The event runs whatever code is in the modulescript. But I always get the same error - about the Player, no matter how I go about it.

Client:

local key = "z"
local Mouse = game.Players.LocalPlayer:GetMouse()
local Player = game.Players.LocalPlayer
SpellDisableCheck = false
Mouse.KeyDown:Connect(function(Key)
    if Key:lower() == key and SpellDisableCheck == false then
        SpellDisableCheck = true
        game.ReplicatedStorage.Resources.MagicEvents.WaterSlicer:FireServer(Player, script.Damage)
        SpellDisableCheck = false
    end
end)

Module:

local WaterMagic = {}
function WaterMagic.Slicer(Player, damage)
    print("z pressed")
    local Animation = Instance.new("Animation")
    Animation.AnimationId = "http://www.roblox.com/asset/?id=357408908"
    local track = Player.Character.Humanoid:LoadAnimation(Animation)
    track:Play()
    local Torso = Player.Character.Torso
    local rand = {0, 15, -15, 45, -45}
    local Part = game.ReplicatedStorage.Resources.Parts:FindFirstChild("WaterSlicer")
    for i = 1, 10 do
        local b = Part:Clone()
        b.CFrame = Torso.CFrame * CFrame.new(math.random(-3, 3), math.random(0, 3), -3) * CFrame.Angles(180, math.rad(rand[math.random(1, #rand)]), 0)
        local f= Instance.new("StringValue", damage)
        f.Name = "Creator"
        f.Value = Player.Name
        local Damage = Instance.new("IntValue", damage)
        Damage.Name = "Damage"
        Damage.Value = 1 + (game.ReplicatedStorage.Resources.Remotes.Functions.GetPlayerStrength:InvokeServer() / 100)
        damage.Disabled = false
        local v = Instance.new("BodyVelocity", b)
        v.maxForce = Vector3.new(math.huge, math.huge, math.huge)
        v.velocity = Torso.CFrame.lookVector * 125
        b.Anchored = false
        game:GetService("Debris"):AddItem(b, 4)
        b.Parent = workspace
        wait()
    end
    track:Stop()
end


return WaterMagic

The serverscript is basically creating a remotevent which requires the module script, and runs the respective function. Just incase I explained this bad, here is the serverscript.

local EventStore = game.ReplicatedStorage.Resources.MagicEvents
local Modules = game.ServerStorage.Magics
---Water Magic
local Water = require(Modules.Water)
local slicer = Instance.new("RemoteEvent", EventStore)
slicer.Name = "WaterSlicer"
slicer.OnServerEvent:Connect(function(Player, Damage)
    Water.Slicer()
end)