User blog comment:InvictusKris/Deck for Springfest/@comment-25383747-20150611172449/@comment-25600444-20150611180513

Ancient World as a whole is not a problem. Sieger Decks, Wild Dragons and Adil Diablos Decks all suffer from one thing. Penetrate.

Since those decks pretty much require that a Size 3 be placed in the Center, Soulguard and other similar effects are pratically useless cause they do not prevent the destruction of the monster, hence Pentrate still activates.

I will say though, Base Cerberus actually sounds pretty good. I could literally call him and a Size 1 "A", use Full Fire to destroy something, then activate ArMored Gate to retrieve said "A" (or whatever) for Soul Benefits.