@09MurphyM
Using monsters as spells and soul stealing, correct? Doesn’t help that the archetypes that don’t use the extra deck had their own field spells that were better, making it practically useless.
@Meanlucario
In the anime it gives you extra monster zones and Monsters in the back row could not be attacked unless you destroyed the ones in the front. Also it couldn’t be destroyed or targeted by enemy card effects. Along with 500 attack boost for all monsters.
Then big bad of the arc got upgrades for it that prevented him taking any direct attack or effect damage. Got pretty ridiculous.