If you have the Harbinger and a bunch of elves out you can tap them to slowly kill off everyone else's creatures, making a slow one-sided board wipe
Since he starts at a power of you need to get him a total of +3 to get him there
Maleficents Staff brings you closer to being able to build a pretty solid deck around this theme, so keep an eye on this card
However, Liliana, the Last Hope pairs perfectly with Grim Flayer in this situation by shrinking the Sylvan Advocate
Grasp of Fate Grasp of Fate is much more efficient than the traditional Oblivion Ring since it strikes all three of your opponents at once, making this a removal spell tailored to Commander
When asked by principal narrative designer Dillon Deveney about the most impressive art he reviewed, Nomura referenced two distinct versions of Sephiroth from Final Fantasy 7