One of my favorite aspects of this game is to take cards that I feel are generally under valued by the community, and demonstrate how they have more value than you might think at first glance. That is pretty easy to do with this card, since most players find no value in it, and have probably never played or thought about playing it.
Basically, what this card does is function as a means to shuffle the encounter deck. This can actually be useful in the following situations:
You have scried the encounter deck and see several rounds of terrible options coming your way. Maybe you are almost location locked and the next few encounter cards are locations? Perhaps you are saturated with enemies and you see two more enemies coming your way. Maybe that game ending treachery is in the line-up and you don't have a A Test of Will yet? Of course this assumes you have a means of scrying, and thus combos with Henamarth Riversong, Rumour from the Earth, Scout Ahead, Palantir, Denethor, and my new favorite scrying tool, Interrogation.
Speaking of Denethor, it actually combos really great with him and this might be one of the most compelling reasons to use this card. The reason is that due to Denethor's ability, you often end up getting an opportunity to bypass really difficult cards and move them to the bottom of the encounter deck. This tends to result in a heavily stacked, nasty "last 5 cards" of the encounter deck when you get to the bottom. The End Comes let's you bypass these and start fresh with a newly shuffled encounter deck. This also works when you have a treachery or other effect "search encounter deck and discard pile for.. then shuffle" effect that shows you that the remaining 8 cards left at the bottom of the deck aren't the ones that you hope to face.
Occasionally, there are cards in the encounter deck that got discarded when you didn't want them to. The one that comes to mind is Ranger of the North, but this can also apply to objective allies, objective attachments, or maybe just a particular location that you would rather see in play that not. The End Comes gives you the means to shuffle these back into the encounter deck once discarded.
- This one is the most quest dependant, but certain quest effects actually trigger off of cards in the encounter deck discard pile. The most obvious example of this are Deadman's Dike with it's dreaded "Cursed Dead" which triggers all other copies to come flying out of the discard pile when revealed. With this card you can reset the discard pile.
Of course, the real issue with this card is the puzzling restriction that doesn't allow you to play it unless a dwarf character leaves play. This alone makes this card fairly difficult to justify outside of dwarf decks, and even within dwarf decks you tend not to see a lot of allies leave play. To my knowledge, there are no "discard for" effects on any dwarf characters. Probably the best way to get around this odd restriction is to include a Miner of the Iron Hills or Erebor Hammersmith. These are cheap dwarf allies that you can use for their "enters play" effects, and then chump block with them to use this card. Luckily, both of these dwarves are in sphere with Denethor and other scrying effects.
It may not be over powered by any stretch of the imagination, but give this card a try sometime. You might find it can be more useful in a pinch than you first thought.