Backed by popular demand (sort of) here's the last Druddigon set as a Specially Defensive set, with slash changes requested by DC.
Druddigon (M) @ Leftovers
Trait: Rough Skin
EVs: 252 HP / 4 Atk / 252 SDef
Careful Nature (+SDef, -SAtk)
- Substitute / Stealth Rock
- Glare
- Dragon Tail / Roar
- Dragon Claw
Role: Special Wall
What it Does: While Druddigon is the best offensive Dragon type in RU, one shouldn't forget about its defenses. 77 / 90 / 90 defenses are pretty good in RU and this allows Druddigon to go with a more defensive set. Its odd movepool also sets Druddigon apart from other walls in the tier. Its well placed resistances to Water, Grass, Fire, and Electric allow it to be a great special wall capable of checking the likes of Sceptile, Manectric, Magmortar, and Rotom-C. Substitute is used to shield Druddigon from otherwise debilitating status such as poison or burn. Glare is a cool paralysis move that isn't widely distributed and it allows Druddigon to safely come in and paralyze many special attackers such as Manectric, Sceptile, and Lilligant. The choice between Dragon Tail and Roar comes down to what you want to phaze through. Dragon Tail is preferred as Druddigon's base 120 Attack stat will make it sting quite a bit after STAB. However, if Sub users such as Sceptile, Mesprit, and Uxie are of more concern to your team, Roar is perfectly viable. Dragon Claw is the preferred last move as it gives Druddigon a reliable STAB move to work with. Stealth Rock can be used if you can't fit another user on your team, but Druddigon has good synergy with most common users of the move.
Good Teammates: Lanturn and Cryogonal are good teammates as both resist Ice attacks and provide additional specially defensive support. Lanturn has access to Heal Bell to cure Druddigon of annoying status while Cryogonal provides Rapid Spin support and has reliable recovery. Speaking of recovery, Wish support is really good since Druddigon doesn't have reliable recovery. Clefable and Alomomola are the most notable thanks to their high HP stats and additional support. Poliwrath is a good partner who can continue the phazing process should Druddigon drag out a physical attacker it would rather not deal with. Hazard support is great to further support Druddigon's phazing tactics. Uxie and Steelix are both reliable SR users while Qwilfish is a good defensive Spiker. All 3 can take most physical attacks aimed at Druddigon.
What Counters It: Klinklang is public enemy #1. It resists Druddigon's STAB, has Sub to block Glare and Dragon Tail, and Shift Gear to boost up and sweep Druddigon's team. If Druddigon lacks Dragon Tail, it will struggle against bulky Taunt users like Drapion (who can also set up SD) Tangrowth generally doesn't care about paralysis since it's slow anyway and can incapacitate Druddigon or the switch-in with Sleep Powder. Escavalier and Aggron don't mind paralysis either and will have no issues with throwing out a powerful Megahorn or Head Smash respectively. Hard hitting physical attackers such as Gallade, Feraligatr, and Crawdaunt can usually punch through Druddigon but a well-timed Glare can cripple them for the match.
Additional Info: Although Druddigon's resistances are better for taking special attacks, Druddigon's equal defenses can allow it to go physically defensive. When Druddigon adopts a physically defensive spread (252 HP / 4 Atk / 252 Def EV spread with an Impish nature should be used) Druddigon can check powerful physical attackers such as Entei and Kabutops. This also allows Druddigon to abuse Rough Skin more effectively and force Entei to take a copious amount of damage from using Flare Blitz. However, Druddigon's resistances are better fit for taking special attacks, so the physically defensive spread should only be used should your team need an answer to the likes of Crawdaunt, Entei, or Kabutops. You also must ask yourself if Poliwrath, a Pokemon with much better physical resistances, would be a better fit for your team. Physically Defensive Druddigon is certainly viable and effective, but just know that the Specially Defensive spread will generally benefit Druddigon more.
Wow, almost felt like doing an analysis lol.