Different printers use different safe margins, but the principle is consistent: dont park your most important details in the danger zone
During the Battle Phase, when a Spell/Trap Card is activated (Quick Effect): You can negate the activation, and if you do, destroy that card, and if you do that, this card gains 500 ATK
These theories came from datamined hidden accessories in the in-game shop, which included references to Lugia and Pichu
Arceus is classified as a 3-Diamonds card in the Triumphant Light set
79699070 Curse of Tri-Horned Dragon 681
Then you can -7 as an ultimate to have your foe exile X cards from their library where X is your exiled mana cost, so that's a win-con over time