SPELL_SHADOWHEAL = 37456 -- cast self
SPELL_SHADOWBOLT = 58827 -- main tank
----------------
SPELL_FROSTARMOR = 18100 -- cast self
SPELL_ICETOMB = 29670 -- random player
----------------
SPELL_FIRESHIELD = 37318 -- cast self
SPELL_FIREBALL = 41484 -- random player
----------------
SPELL_LIGHTNINGSHIELD = 59845 -- cast self
SPELL_LIGHTNINGBOLT = 52921 -- random player
----------------
SPELL_ARCANEBOLT = 59520 -- random player (ranged)
SPELL_DEATH = 5 -- random player

local self = getfenv(1)

function OnCombat(Unit, event)
Unit:SendChatMessage(14, 0, "Ha puny humans, you dare challenge me!")
self[tostring(Unit)] = {
    --------------
    shadowheal = 5, -- phase 1 spells
    shadowbolt = 6, -- phase 1 and start spells
    --------------
    frostarmor = 1, -- * phase 2 spells
    icetomb = 6, -- phase 2 spells
    --------------
    fireshield = 1, -- * phase 3 spells
    fireball = 6, -- phase 3 spells
    --------------
    lightningshield = 15, -- phase 4 spells
    lightningbolt = 2, -- phase 4 spells
    --------------
    arcanebolt = 4, -- phase 5 spells
    --------------
    death = 5, -- phase 6 spells
    --------------
    phaseid = 0 -- phase controller
}
Unit:RegisterAIUpdateEvent(1000)
end

function AIupdate(Unit)
if(Unit:IsCasting() ) then return end
    if(Unit:GetNextTarget() == nil) then
        Unit:WipeThreatList()
        return
    end
local vars = self[tostring(Unit)]
if(Unit:GetHealthPct() > 90)then -- start phase
    vars.shadowbolt = vars.shadowbolt - 1
    if(vars.shadowbolt <= 0)then
        Unit:FullCastSpellOnTarget(SPELL_SHADOWBOLT, Unit:GetMainTank())
        vars.shadowbolt = 6
    end
elseif(Unit:GetHealthPct() > 80 and Unit:GetHealthPct() <= 90 and vars.phaseid == 0)then -- phase 1 transition
    Unit:SendChatMessage(14, 0, "I shall never fall!")
    vars.phaseid = 1
elseif(Unit:GetHealthPct() > 80 and Unit:GetHealthPct() <= 90 and vars.phaseid == 1)then -- phase 1
    vars.shadowbolt = vars.shadowbolt - 1
    vars.shadowheal = vars.shadowheal - 1
    if(vars.shadowbolt <= 0)then
        Unit:FullCastSpellOnTarget(SPELL_SHADOWBOLT, Unit:GetMainTank())
        vars.shadowbolt = 6
    elseif(vars.shadowheal <= 0)then
        Unit:CastSpell(SPELL_SHADOWHEAL)
        vars.shadowheal = 5
    end
elseif(Unit:GetHealthPct() > 60 and Unit:GetHealthPct() <= 80 and vars.phaseid == 1)then -- phase 2 transition
    Unit:SendChatMessage(14, 0, "So you think that was hard, Ha!")
    Unit:SetModel(6209)
    vars.phaseid = 2
elseif(Unit:GetHealthPct() > 60 and Unit:GetHealthPct() <= 80 and vars.phaseid == 2)then -- phase 2
    if(Unit:HasAura(SPELL_FROSTARMOR) == false)then
        Unit:CastSpell(SPELL_FROSTARMOR)
    end
    vars.icetomb = vars.icetomb - 1
    if(vars.icetomb <= 0)then
        Unit:FullCastSpellOnTarget(SPELL_ICETOMB, Unit:GetRandomPlayer(0))
        vars.icetomb = 6
    end
elseif(Unit:GetHealthPct() > 40 and Unit:GetHealthPct() <= 60 and vars.phaseid == 2)then -- phase 3 transition
    Unit:SendChatMessage(14, 0, "Time for things to get hotter!")
    Unit:SetModel(1070)
    Unit:SetScale(2)
    if(Unit:HasAura(SPELL_FROSTARMOR))then
        Unit:RemoveAura(SPELL_FROSTARMOR)
    end
    vars.phaseid = 3
elseif(Unit:GetHealthPct() > 40 and Unit:GetHealthPct() <= 60 and vars.phaseid == 3)then -- phase 3
    if(Unit:HasAura(SPELL_FIRESHIELD) == false)then
        Unit:CastSpell(SPELL_FIRESHIELD)
    end
    vars.fireball = vars.fireball - 1
    if(vars.fireball <= 0)then
        Unit:FullCastSpellOnTarget(SPELL_FIREBALL, Unit:GetRandomPlayer(0))
        vars.fireball = 6
    end
elseif(Unit:GetHealthPct() > 20 and Unit:GetHealthPct() <= 40 and vars.phaseid == 3)then -- phase 4 transition
    Unit:SetScale(1)
    if(Unit:HasAura(SPELL_FIRESHIELD))then
        Unit:RemoveAura(SPELL_FIRESHIELD)
    end
    Unit:SetModel(14515)
    vars.phaseid = 4
elseif(Unit:GetHealthPct() > 20 and Unit:GetHealthPct() <= 40 and vars.phaseid == 4)then -- phase 4
    vars.lightningshield = vars.lightningshield - 1
    vars.lightningbolt = vars.lightningbolt - 1
    if(vars.lightningshield <= 0)then
        Unit:CastSpell(SPELL_LIGHTNINGSHIELD)
        vars.lightningshield = 15
    elseif(vars.lightningbolt <= 0)then
        Unit:FullCastSpellOnTarget(SPELL_LIGHTNINGBOLT, Unit:GetRandomPlayer(0))
        vars.lightningbolt = 2
    end
elseif(Unit:GetHealthPct() > 5 and Unit:GetHealthPct() <= 20 and vars.phaseid == 4)then -- phase 5 transition
    if(Unit:HasAura(SPELL_LIGHTNINGSHIELD))then
        Unit:RemoveAura(SPELL_LIGHTNINGSHIELD)
    end
    Unit:SetModel(14253)
    vars.phaseid = 5
elseif(Unit:GetHealthPct() > 5 and Unit:GetHealthPct() <= 20 and vars.phaseid == 5)then -- phase 5
    vars.arcanebolt = vars.arcanebolt - 1
    if(vars.arcanebolt <= 0)then
        Unit:FullCastSpellOnTarget(SPELL_ARCANEBOLT, Unit:GetRandomPlayer(1))
    end
elseif(Unit:GetHealthPct() <= 5 and vars.phaseid == 5)then -- phase 6 transition
    Unit:SendChatMessage(14, 0, "Enough! This must end!")
    Unit:SetModel(3980)
    vars.phaseid = 6
elseif(Unit:GetHealthPct() <= 5 and vars.phaseid == 6)then -- phase 6
    vars.death = vars.death - 1
    if(vars.death <= 0)then
        Unit:FullCastSpellOnTarget(SPELL_DEATH, Unit:GetRandomPlayer(0))
    end
end
end

function OnDied(Unit, event)
Unit:SendChatMessage(14, 0, "How.. How can this be!")
Unit:RemoveEvents()
Unit:RemoveAIUpdateEvent()
Unit:DeMorph()
Unit:SetScale(1)
end

function OnLeaveCombat(Unit, event)
Unit:RemoveAura(SPELL_LIGHTNINGSHIELD)
Unit:RemoveAura(SPELL_FIRESHIELD)
Unit:RemoveAura(SPELL_FROSTARMOR)
Unit:SetScale(1)
Unit:RemoveEvents()
Unit:RemoveAIUpdateEvent()
Unit:DeMorph()
end

function OnKIllPlayer(Unit, event, pDied)
if(pDied:IsPlayer())then
    Unit:SendChatMessage(14, 0, "Ha your strength is puny!")
end
end

RegisterUnitEvent(38581,1,OnCombat)
RegisterUnitEvent(38581,2,OnLeaveCombat)
RegisterUnitEvent(38581,4,OnDied)
RegisterUnitEvent(38581,21,AIupdate)