Absol

While it's a bit too frail to function well in higher tiers, Absol has cemented itself as one of the best Dark-types and overall offensive Pokemon in RU, and it's not hard to see why. Absol is well-known for possessing what is bar none the most powerful priority move in the entire game in the form of its STAB Sucker Punch, and this is what makes it so dangerous in RU, as it makes up for Absol's average Speed stat, revenge kills a slew of threats such as Accelgor, Rotom-C, and Sceptile, and cleans up rather nicely late-game. Outside of this powerful move, Absol happens to be one of the best users of Pursuit in the tier, trapping and eliminating threats such as Slowking, Uxie, Mesprit, and Rotom for its teammates and starting mind games with the opponent in combination with Sucker Punch. Combine these two moves with Swords Dance, a high critical hit ratio thanks to Super Luck, and coverage moves to get past would-be checks such as Tangrowth, Steelix, and Escavalier, and Absol makes for a great offensive Pokemon. Keep in mind, however, that Absol struggles quite a bit with its frailty; most decently powerful moves will 2HKO Absol at worst, making it very hard to switch in and set up a Swords Dance. Absol struggles with Sucker Punch's drawback too, as faster Pokemon with the appropriate moves can force Absol into unfavorable situations and eventually play around it. All in all, despite these setbacks, underestimating Absol is a grave mistake, as one wrong move against it can mean the difference between a win and a loss.