Guardian - Dastardes, true to its Grim Reaper-like appearance, was a Monster that was literally immortal. Whether destroyed by battle or Effect Destruction, no matter how many times it was destroyed, it could revive from the Graveyard. And each time it revived by discarding a Monster Card to the Graveyard, it would grow even stronger.
Originally, this effect could not truly be called complete "immortality," because its revival did not come without a price. Every time Dastardes revived, its effect was a Forced Activation. The player had to discard a card from their hand to revive it, even if its controller no longer wished to activate the effect.
The design of this effect seemed to symbolize how "once one fell into darkness, one could no longer pull oneself free." Once it appeared on the field, even Rafael himself could no longer control it.
But because a card had to be discarded from the hand each time it revived, the number of revivals was naturally limited. In fact, in the original work, Atem had defeated Dastardes by exploiting this weakness. Once Rafael's Number of Cards in Hand was exhausted, Dastardes' revival tokens were gone as well, and this Guardian would be completely destroyed.
However, at this moment, the Continuous Spell "Card of Safe Return" perfectly made up for that weakness.
Every discarded card allowed Dastardes to revive, and every revival let Rafael draw three cards. As Dastardes continued reviving, its ATK would rise higher and higher, while Rafael's hand resources would steadily increase. Spending one revival token gained him three more; it was practically Infinite Life.
This changed the condition for exhausting its revival tokens from "depleting the opponent's hand" to "drawing the opponent's Deck dry," vastly increasing the difficulty.
Furthermore, the common tactic against indestructible Monsters—accepting that they still had