Ralts itself is not particularly powerful, but once it reaches its final Evolution, it can either become a powerful Fairy known as Gardevoir, or a Fighting-type known as Gallade
Of course, the Reanimator player casting this on turn one or two will frequently be bringing back Grave Titan or Archon of Cruelty, while the other player may not even have a creature in their graveyard yet to choose making this one of the very best early game reanimation spells ever
Some of the monsters you'll be able to collect are Greninja, Lapras, Drifloon, Zorua, Ho-Oh, Xerneas, Kyogre, Lunala, Zekrom, Zacian, Slowpoke (in a well!), Unown, and Meowth, among others
Number 96 also enjoys sadistically manipulating his hosts and brutally defeating his enemies
Ob Nixilis is an example of a high-impact card