Earthshaker Khenra

If the card copied by the token had any "when [this permanent] enters the battlefield" abilities, then the token also has those abilities and will trigger them when it's created. Similarly, any "as [this permanent] enters the battlefield" or "[this permanent] enters the battlefield with" abilities that the token has copied will also work.

Spells, activated abilities, and triggered abilities can't raise Earthshaker Khenra's power before you have to choose a target for its ability. Static abilities, such as that of Lord of the Accursed, will raise its power in time to let you target a larger creature.

Once you've activated an eternalize ability, the card is immediately exiled. Opponents can't try to stop the ability by exiling the card with an effect such as that of Crook of Condemnation.

The target creature's power is checked when you target it with Earthshaker Khenra's ability and when that ability resolves. Once the ability resolves, if the creature's power increases or Earthshaker Khenra's power decreases, the target creature will still be unable to block.

If a creature card with eternalize is put into your graveyard during your main phase, you'll have priority immediately afterward. You can activate its eternalize ability before any player can try to exile it, such as with Crook of Condemnation, if it's legal for you to do so.

For each card with eternalize, a corresponding game play supplement token can be found in some Hour of Devastation booster packs. These supplements are not required to play with cards with eternalize; you can use the same items to represent an eternalized token as you would any other token.