Hello!

It would be great if you could clarify the following card interaction to me.

Azrael controls Rest in Peace and Helm of Obedience. Belzebub controls Wheel of Sun and Moon enchanting himself. Azrael activates the ability of the Helm targeting Belzebub and it starts resolving. What will happen?

I know that, for each card milled by the Helm's ability, Belzebub chooses whether to apply the effect of RiP or Wheel (i.e. whether to put the card into exile or back on the bottom of his library). The question is: do game rules (716.3) force Belzebub to break the loop which leads to drawing the game (by choosing Wheel each time)? Is Belzebub forced to choose RiP replacement effect to end the loop by having all his library exiled? If so, at which point does he have to choose RiP's effect (after how many cards being put from the top to the bottom of his library)?

Thank you,

Milan

Yes, Belzebub is forced to break the loop by choosing to apply Rest in Peace first, and will thus eventually be forced to empty his library.

Belzebub can choose to put any number of cards from the top to the bottom of his or her library before breaking the loop, but whether it's ten or twenty or seventy billion, he's still going to end up with an empty library. Just as with the lifegain loop scenario, he's not allowed to waste time with meaningless continuations of the loop.