Still, it's a potent and iconic card, well deserving of high placing on this list
The closest legal comparison to GriselbrandGriselbrand would be NecropotenceNecropotence, which is already a Game Changer, but the steps necessary for exploiting GriselbrandGriselbrand are far less demanding than the hoops required to jump through to break NecropotenceNecropotence
If Underworld Sentinel returns to the battlefield later, it'll be a new object with no memory of the creatures it exiled previously
If you choose to cast it for its Bestow cost, it instead enters as an Aura enchanting a creature, getting whatever abilities and bonuses are granted according to the enchantment creatures text box
With some minor upgrades, such as Snow White, Unexpected Houseguest and Nick WIlde, Wily Fox, this deck can quickly become a lot more viable