Basically a server script that reduces the stamina when the event has been called. I don't know why but the IntValue inside the StaminaGui doesn't change.
--//Services
local replicatedStorage = game:GetService('ReplicatedStorage')
local gui = game:GetService('StarterGui')
--//Variables
local rollEvent = replicatedStorage:WaitForChild('RollEvent')
local stamina = gui:WaitForChild('StaminaGui'):WaitForChild('Stamina')
--//OnServerEvent
rollEvent.OnServerEvent:Connect(function(player)
stamina.Value = stamina.Value - 25 -- reduce stamina
end)

1 comment
you're changing it in startergui, which means you wont see the change until the character respawns