Fill your deck with cheap Elves, sacrifice outlets, and cards that dump creatures into your graveyard
The cards ability can be activated, unusually, on your opponents turn (albeit just once per turn!): when your number of Life cards reaches 0, you can add 1 card from the top of your deck to the top of your Life cards though you must then trash 1 card from your hand
The beauty of the card is in its flexibility, though: you can build in packages of artifacts, enchantments, or the like, and power them out with a well-timed Umori play, giving you a lot of options that a companion brew just wouldnt offer.
There are also scaling threats that get stronger with each discard
Indeed, it can be highly advantageous for your own purposes to draw off of other players fighting each other though you can get some occasional side eye in the process
The Tera Charizard is one of the best pulls from this set , as well as the shiny Mew ex, a full art Gardevoir, and a Miraidon ex, which are all well worth finding