Registeel

Registeel's excellent bulk and great defensive typing make it one of the most resilient defensive Pokemon in RU. Key resistances to Flying, Fairy, Grass, and Dragon allow it to pivot into threats such as Crobat, Togekiss, Gardevoir, Roserade, and Noivern. This is supplemented by its great natural bulk, which allows it to also take powerful neutral hits from the likes of Xurkitree and Toxtricity. Registeel also has Stealth Rock, and its ability to annoy common Defoggers like Togekiss and Crobat makes it a good user of the move. Registeel is unfortunately reliant on its Leftovers to stay healthy, which makes Knock Off incredibly threatening to it. Registeel is also rather passive compared to other Steel-types, as it is much more reliant on the likes of Toxic to make progress than its Steel-type competition of Steelix and Metagross. Annoying weaknesses to Fire-, Ground-, and Fighting-type moves leaves Registeel open to common Pokemon such as Flygon, Nidoqueen, and Heracross.