Landorus, Thundurus, Tornadus, Latias, Latios, Moltres, Zapdos, Articuno, Raikou, Suicune, Entei, Terrakion, Virizion, Registeel, Regirock, Regice, Regigigas. I think those are all of them, but I'm not sure. Latios killed me last time because he was holding Bright Powder or whatever it was so my attacks missed. The main legends that I have trouble with are Latios, Landorus, Thundurus and Tornadus. I don't know how to beat them. I'd gladly use my own legends if I had good ones, but sadly I do not.

EDIT: I think most of what the legendaries use is here http://www.serebii.net/xy/battlemaison.shtml. Which means Latios would probably actually be using Lax Incense.

EDIT #2: Just acquired a 5IV (-SP. ATK) Jolly Terrakion from someone. Perhaps with that nice speed and attack he could prove useful?

Jolly Terrakion is great. Use a Choice Scarf or Choice Band on him and spam attacks, things will die. Also a super easy way to destroy any in-game opponent is to use Adamant Haxorus + Dragon Dance -> Outrage/Earthquake spam until everything dies.

True but I would keep in mind that you can't just smack one on every team.

If you're playing cartridge, you can. AI is easy with any boosting set.

I got a hasty, freshly hatched Eevee with egg moves in wonder trade. Immediately used a thunder stone on it.

So there ARE generous people that use wonder trade.... XD

I ended up going with this one guy's team on YouTube who got a 200 win streak. I finally got to 50 and won, but I must suck because at 54 I lost to Tentacruel using Toxic on my Chansey. Still though. That mansion the RNG is always in the CPU favor. Quick Claw always works and Attack Boosts always happen. It's the worst experience from my whole time playing that game.

Glaceon is my favorite Eeveelution and I want to add her on my team, but to me the EV spread dosen't make sense. Smogon suggests 252 EV spread for speed? I don't see what Pokemon it's really going to outspeed. I feel like it's a waste and could be invested in Defense or another stat. Am I missing something?

Base 65 neutral natured with max investment secures the outspeed on a lot of key uninvested threats. For example, Glaceon gets 229 with 252 Modest and gets the jump on 44 Speed Rotom-W (which is in turn invested to get the jump on 252+ Azu). It however misses the jump on Adamant Brelooms and Bisharps just barely, who are really key. Timid nature allows you to get the jump on those two and 252+ (max invested Jolly) Tyranitar, and all uninvested base 100's like pixies (100 base across all stats) which is important as well. But you can go ahead and spec 252 into HP to increase bulk by a considerable amount and go Modest, it won't be too bad.

So should I go with 252 HP/252 SP.ATK/4 SP. DEF for Modest nature? I heard Glaceon is one of the lesser useful Eeveelutions now which makes me sad. Snow Cloak would have been a good ability to use, but I heard Smogon banned it so I went with Ice Body. For the moveset I have Ice Beam/Hidden Power Ground/Yawn/???.

Yeah, that seems like a fine spread for a bulky attacker. I would personally use HP Electric for dat BoltBeam coverage, but it's up to you. Maybe some Fire coverage alongside that if Glaceon gets any somehow? Vast majority of the time you'll probably just be spamming Ice Beam because of STAB though.

Martyrdom Talonflame + Kyurem-B = GG

http://replay.pokemonshowdown.com/ou-125057754

+ no matter how ****ty you misplay things, never surrender (i was hoping for a focus miss)

http://replay.pokemonshowdown.com/ou-125407845

Glaceon is so adorable <3 Thanks for the recommendations! Except I still don't know what to do for the fourth move. Maybe Signal Beam or something.

Just so you know
Nintendo just filed a trademark for the name Pokemon Delta Emerald

k bye

^Cool.

What moveset should I have for my Jolteon if he only has Hidden Power Dragon? Should I aim for HP Ice (which will be difficult to obtain) or try something else?

HP Ice is king on Jolteon. BoltBeam coverage is almost mandatory, willing to bet more than 90% of Special Electric attackers types run HP Ice or Ice Beam. Even my physically-invested Thundurus runs HP Ice. BoltBeam lets you hit a huge amount of Pokemon for at least neutral.