For three mana, you get a 1/3 that makes it so that whenever you gain life, you can have an opponent lose that much life
Gitaxian Probe is the other interesting one here since it costs a blue Phyrexian mana (meaning you can pay two life instead of a blue mana), letting you peek at a players hand and draw a single card
When descend is part of a triggered ability, it is usually conditional (At the beginning of your end step, if you descended this turn)
Played using Ink just like any other card, and laid on the table horizontally, each Location offers different benefits, with many giving their controlling player Lore at the start of their turn
As effective as this strategy can be, realistically, its just the tip of the iceberg, since Eye of Nidhogg can enchant any creature
Ideally, you want to attack with Atarka, either by giving it haste or by having it in play next turn