Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If you control no monsters, you can Special Summon this card (from your hand). If this card destroys an opponent's monster by battle: This card gains 500 ATK. If this card is destroyed by battle: The monster that destroyed it loses 500 ATK.
--カイザー・ブラッド・ヴォルス
--Kaiser Vorse Raider
local s,id=GetID()
function s.initial_effect(c)
	--spsummon proc
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetType(EFFECT_TYPE_FIELD)
	e1:SetCode(EFFECT_SPSUMMON_PROC)
	e1:SetProperty(EFFECT_FLAG_UNCOPYABLE)
	e1:SetRange(LOCATION_HAND)
	e1:SetCondition(s.spcon)
	c:RegisterEffect(e1)
	--atkup
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_ATKCHANGE)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e2:SetCode(EVENT_BATTLE_DESTROYING)
	e2:SetCondition(aux.bdocon)
	e2:SetOperation(s.atkop)
	c:RegisterEffect(e2)
	--atkdown
	local e3=Effect.CreateEffect(c)
	e3:SetDescription(aux.Stringid(id,2))
	e3:SetCategory(CATEGORY_ATKCHANGE)
	e3:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e3:SetCode(EVENT_BATTLE_DESTROYED)
	e3:SetOperation(s.desop)
	c:RegisterEffect(e3)
end
function s.spcon(e,c)
	if c==nil then return true end
	return Duel.GetFieldGroupCount(c:GetControler(),LOCATION_MZONE,0,nil)==0
		and Duel.GetLocationCount(c:GetControler(),LOCATION_MZONE)>0
end
function s.atkop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsRelateToEffect(e) and c:IsFaceup() then
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_UPDATE_ATTACK)
		e1:SetValue(500)
		e1:SetReset(RESET_EVENT|RESETS_STANDARD_DISABLE)
		c:RegisterEffect(e1)
	end
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local tc=c:GetBattleTarget()
	if not tc:IsRelateToBattle() or tc:IsFacedown() then return end
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_UPDATE_ATTACK)
	e1:SetReset(RESET_EVENT|RESETS_STANDARD)
	e1:SetValue(-500)
	tc:RegisterEffect(e1)
end