The
(This card is also always treated as "Legendary Dragon Critias".)
Send 1 Trap from your hand or field to the GY, that is listed on a Fusion Monster that can only be Special Summoned with "The Fang of Critias" (if that card is Set, reveal it), then Special Summon that Fusion Monster from your Extra Deck. You can only activate 1 "The Fang of Critias" per turn.
local s, id, o = GetID()
function s.initial_effect(c)
	--Activate
	local e1 = Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetCountLimit(1, id + EFFECT_COUNT_CODE_OATH)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
	--add code
	local e2 = Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_ADD_CODE)
	e2:SetProperty(EFFECT_FLAG_CANNOT_DISABLE + EFFECT_FLAG_UNCOPYABLE)
	e2:SetValue(10000060)
	c:RegisterEffect(e2)
end
function s.tgfilter(c, e, tp)
	return c:IsType(TYPE_TRAP) and Duel.IsExistingMatchingCard(s.spfilter, tp, LOCATION_EXTRA, 0, 1, nil, e, tp, c:GetCode(), c)
end
function s.spfilter(c, e, tp, code, tc)
	return c:IsType(TYPE_FUSION) and c.material_trap and c:IsCanBeSpecialSummoned(e, 0, tp, true, false) and code == c.material_trap and Duel.GetLocationCountFromEx(tp, tp, tc, c) > 0
end
function s.target(e, tp, eg, ep, ev, re, r, rp, chk)
	if chk == 0 then
		return Duel.IsExistingMatchingCard(s.tgfilter, tp, LOCATION_HAND + LOCATION_SZONE, 0, 1, nil, e, tp)
	end
	Duel.SetOperationInfo(0, CATEGORY_SPECIAL_SUMMON, nil, 1, tp, LOCATION_EXTRA)
end
function s.activate(e, tp, eg, ep, ev, re, r, rp)
	Duel.Hint(HINT_SELECTMSG, tp, HINTMSG_FMATERIAL)
	local g = Duel.SelectMatchingCard(tp, s.tgfilter, tp, LOCATION_HAND + LOCATION_SZONE, 0, 1, 1, nil, e, tp)
	local tc = g:GetFirst()
	if tc and not tc:IsImmuneToEffect(e) then
		if tc:IsOnField() and tc:IsFacedown() then
			Duel.ConfirmCards(1 - tp, tc)
		end
		local code = tc:GetCode()
		Duel.SendtoGrave(tc, REASON_EFFECT)
		if not tc:IsLocation(LOCATION_GRAVE) then
			return
		end
		Duel.Hint(HINT_SELECTMSG, tp, HINTMSG_SPSUMMON)
		local sg = Duel.SelectMatchingCard(tp, s.spfilter, tp, LOCATION_EXTRA, 0, 1, 1, nil, e, tp, code, nil)
		local sc = sg:GetFirst()
		if sc then
			Duel.BreakEffect()
			Duel.SpecialSummon(sc, 0, tp, tp, true, false, POS_FACEUP)
			sc:CompleteProcedure()
		end
	end
end


The
(This card is also always treated as "Legendary Dragon Critias".)
Send 1 Trap from your hand or field to the GY, that is listed on a Fusion Monster that can only be Special Summoned with "The Fang of Critias" (if that card is Set, reveal it), then Special Summon that Fusion Monster from your Extra Deck. You can only activate 1 "The Fang of Critias" per turn.
-- The
local s, id, o = GetID()
function s.initial_effect(c)
	--Activate
	local e1 = Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetCountLimit(1, id + EFFECT_COUNT_CODE_OATH)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
	--add code
	local e2 = Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_ADD_CODE)
	e2:SetProperty(EFFECT_FLAG_CANNOT_DISABLE + EFFECT_FLAG_UNCOPYABLE)
	e2:SetValue(10000060)
	c:RegisterEffect(e2)
end
function s.tgfilter(c, e, tp)
	return c:IsType(TYPE_TRAP) and Duel.IsExistingMatchingCard(s.spfilter, tp, LOCATION_EXTRA, 0, 1, nil, e, tp, c:GetCode(), c)
end
function s.spfilter(c, e, tp, code, tc)
	return c:IsType(TYPE_FUSION) and c.material_trap and c:IsCanBeSpecialSummoned(e, 0, tp, true, false) and code == c.material_trap and Duel.GetLocationCountFromEx(tp, tp, tc, c) > 0
end
function s.target(e, tp, eg, ep, ev, re, r, rp, chk)
	if chk == 0 then
		return Duel.IsExistingMatchingCard(s.tgfilter, tp, LOCATION_HAND + LOCATION_SZONE, 0, 1, nil, e, tp)
	end
	Duel.SetOperationInfo(0, CATEGORY_SPECIAL_SUMMON, nil, 1, tp, LOCATION_EXTRA)
end
function s.activate(e, tp, eg, ep, ev, re, r, rp)
	Duel.Hint(HINT_SELECTMSG, tp, HINTMSG_FMATERIAL)
	local g = Duel.SelectMatchingCard(tp, s.tgfilter, tp, LOCATION_HAND + LOCATION_SZONE, 0, 1, 1, nil, e, tp)
	local tc = g:GetFirst()
	if tc and not tc:IsImmuneToEffect(e) then
		if tc:IsOnField() and tc:IsFacedown() then
			Duel.ConfirmCards(1 - tp, tc)
		end
		local code = tc:GetCode()
		Duel.SendtoGrave(tc, REASON_EFFECT)
		if not tc:IsLocation(LOCATION_GRAVE) then
			return
		end
		Duel.Hint(HINT_SELECTMSG, tp, HINTMSG_SPSUMMON)
		local sg = Duel.SelectMatchingCard(tp, s.spfilter, tp, LOCATION_EXTRA, 0, 1, 1, nil, e, tp, code, nil)
		local sc = sg:GetFirst()
		if sc then
			Duel.BreakEffect()
			Duel.SpecialSummon(sc, 0, tp, tp, true, false, POS_FACEUP)
			sc:CompleteProcedure()
		end
	end
end

