May I recommend a timid, or a hasty nature? If you are using diancie on a team, chances are high youre using it as an yveltal check. Needless to say, with a -spdef nature yveltal doesnt really care about diancie and just breezes past it. I don't like 0/0 bulk in the first place, because diancie is supposed to be bulky and not be a "sweeper". Like max speed does virtually nothing for it, adamant ray is a good benchmark already. Anyway, in reality you'll unlikely be able to fit another good check to yvetal because of the way your build has to turn out. If you do add one, youre likely having a sub-optimal build because youre focusing on one mon with 2 different aspects of your team, which gives you a bit of a redundant build. With a -atk nature you dont have the unneeded drop, and -atk changes almost nothing. The main target of diamond storm, ho-oh, is still ohkoed. Moonblast/earth power hits most stuff anyway, so you lose almot nothing from the 10% drop in attack. A -def nature also doesnt really matter because you die to ho-oh's eq anyway, and you outspeed things like rayq. Eq mence just ohkoes, but I guess having a neutral nature is better for a one-time DE mence check.I wanted to post a core here that I used lately and that gave me good results in ladder:
Ho-Oh @ Choice Band
Trait: Regenerator
EVs: 248 HP / 208 Atk / 52 SDef
Adamant Nature (+Atk, -SAtk)
- Brave Bird
- Sacred Fire
- Earthquake
- Sleep Talk
Diancie @ Diancite
Trait: Clear Body
EVs: 4 HP / 252 SAtk / 252 Spd
Naive Nature (+Spd, -SDef)
- Moon Blast
- Diamond Storm
- Earth Power
- Protect
That's clearly an offensive one, I think that I haven't to say much about that core since it speaks by itself, but Ill introduce it a bit. One of Ho-Oh's biggest flaws as you guys already know is the huge weakness to Stealth Rock and Mega Diancie with Magic Bounce mitigates it a bit. Ho-Oh helps Diancie too as it forces out Scizor and other Steel-type mons which threatnens Diancie, that is cool because it can 2HKO Pdon with Earth Power even if it's running a SDef set so Ho-Oh can spam its STAB fire more easily. Also Ho-Oh covers the weakness to ground that Diancie has, while the latter can switch-in on some Rock-type attacks (don't forget that it hasn't a really good bulk, though). Another niche that Diancie has is that it can revenge-kill SD Rayquaza if it can live an +2 ES, which is always nice as Rayquaza becomes a more dangerous pokèmon in ORAS. The core has obviously problems with strong Water-type attackers like Primal Kyogre and CM Arceus Water, therefore probably the best teammate for it are Primal Groudon to have a safe switch-in on strong Water-type attacks and one Lati Twin to act as a defogger in case Diancie can't prevent Stealth Rock and as well as another check to Primal Kyogre and other Water-type mons. I forget to say that you can run another move instead of Protect on Diancie even if it's probably the best one in Ubers as it's difficult to mega-evolve in a safe way Diancie, but you can always try options like Calm Mind which help you against fat n bulky teams. However, I would always run Protect for the reason I explained before and I'll use a mon that can help against bulkier playstyles. Thats all I guess, thanks for reading and have fun using this core! :]
I mean, it's your set so you could just change it to -atk, but max speed really doesnt do much. The best thing is speedtying (word?) with the latis, but without any bulk diancie is so frail it cant switch in on psyshock anyway. Max hp does wonders for it, because it has a shitty hp stat but good defenses. It's also rather annoying when you cant switch in on anything. Diancie isnt exactly strong enough to be a glass cannon, but when it doesnt have the bulk to switch in on and pressure the opposing team with its great coverage it turns out lacklustre. A spread of 240 HP / 100 SpA / 168 Spe Modest may not outspeed the latis, but at least it now has some bulk to switch in on them. It outspeeds max speed yveltal, and hits just as hard as the 252/252+ spread. You essentially went from speedtying with the latis, to having a mon that actually does what it's supposed to do :] Other than that, this core is good imo. I dont think diancie is actually that great, but in combo with ho-oh it just seems to do well. Yeah, you still need reliably defog or else ho-oh will be hard to use. This pushes your build into the direction of either arceus ghost/gira-o/latias, and then the leftover 2 mon+what you want to do with the don set. The fact that you can use this as your yveltal check is just so nice, and diancie is a pain in the ass to kill, especially if you have a ho-oh backing it up.