I mean, as long as he has at least one Soul Warden effect out there hes by and large immune to non-lethal amounts of damage (in fact, he net-gains life with Healer of the Pride), so as long as he has more life than lands, hes pretty safe to chunk people down for 10+ damage per turn in the late game
Dialga ex has the potential to be meta-defining
11.3 If a Seller withdraws a Lot from sale after the Company has advertised and/or catalogued the Lot for auction but before the Lot has been put on view, the Seller shall pay to the Company the Expenses plus a withdrawal fee equal to 25% plus GST of the higher of: (a) the average of the Estimated Selling Range high and low estimates
If you miss one during the event, these can be found randomly in the Space-Time Smackdown expansion booster packs in-game
C Common Grave Ohja X EARTH Level 4 [ RockEffect ] ATK 1600 DEF 1500 While there is a face-down Defense Position monster(s) on your side of the field, no player can select this card as an attack target
Its a simple 2/2 that you can sacrifice to destroy any nonbasic land, which makes it a nightmare for multicolor strategies