[Note: this guide is how to get your 500 win streak achievement for the achievement points. For the basics of arena, check out the guides such as this one on Arena AI.

The biggest obstacle to getting your 500 win streak w/ maximum point bonuses is getting toasted by either an unlucky random rule, or bad RNG. Luckily for us, there's a way to design your arena team around these.

Random Rules:

• BB gauge starts at zero

• BB disabled

• Atk Halved

• Random Status Ailments

• Fire Advantage

• Water Advantage

• Earth Advantage

• Thunder Advantage

• Dark Advantage

• Light Advantage

• Male Advantage

• Female Advantage

• Genderless Advantage

• LS Disabled

• Sphere Disabled

1) The first thing I would recommend is having a good variety of units, preferably as many 7* as possible that will fit in your team. Have a mix of male, female or genderless units in your team, and have multiple elements. This way it's impossible for your entire team to have a disadvantage. And as long as one of your unaffected units BBs/SBBs, you'll wipe out your opponent. (of note: put any 6* or low HP units at the 2nd slot from top or at bottom if possible, that spot tends to get less chance of being wiped out)

2) Have Selena on your team. Her ES will save you if RNG decides to screw you. Secondary sphere is ideally a status immunity sphere if you're not running a status immunity leader. This protects her from getting paralyzed by random rule, or cursed by your opponent. Place her at the top, for best chance of BBing. Everyone else place based on their arena AI type. Feeva is also excellent too, with her ES helping her survive. Magress also gets special mention for being able to fill his BB with Leomurg in a 0-start BB round with minimal assistance. And Tora and Kikuri have a low chance of inflicting status ailments when attacking on ES.

3) HP boosting and BB filling leader, ideally with status immunity. Currently there's only Griel who fits this description, but there will probably be more later. With her as lead, you can never be paralyzed by random rule or cursed by opponent's Elza or Kikuri. Status infliction rule on the contrary, becomes a huge advantage if you pick an opponent whose leader lacks status immunity. BB will always fill well, even if you start from 0 or without spheres. Assuming you're running a mixed team, you'll never have your whole team in elemental or gender disadvantage.

4) Lastly, choose your opponent wisely. The absolute safest, RNG-proof way to win 100% in addition to the above tips, is to fight 6* BB filling leads and old weak 6* teams. There are plenty of these way up through very high arena ranks. For example: Uda, Dia, Lodin, Elza, Zelnite, Lucca, Kuda, Ardin, Felneus, 6* Starters, 6* Kikuri/Sefia, Lilith other 6* Rainbow leaders, Karl leaders are some of the ones I see most often. Avoid: Lilly Matah, Orna, Maxwell, Lugina and Lunaris, Zurg, Grah/Owen and all 7* leaders. If you're feeling lucky Ruby or Raga leaders are usually fairly safe to fight, but every now and then opponent team will land a lucky spark kill.

If your team, mixed 7* team with Griel leader fights say, a Zelnite leader team full of 6*, there is literally no rule or RNG that can kill you. No BB round will still win, thanks to your units being HP boosted with higher stats. No LS? Selena can still fill BB almost by herself. With HP lead if RNG decides to mess with you and none of your BBs fire in the few turns, but your opponent does, your team can even tank up to 2-3 BBs (opponents don't get SBB in arena). And Selena can even survive into a fourth turn with her angel idol. If you don't have Griel, Kanon is a fairly good substitute. Your units will need more help filling BB though, you may want to put in units with high BC production like Zel Deus.

Bestie is also an excellent arena leader, with HP boost, excellent BB filling but no status immunity. Put refined gem or other status immunity on at least two of your units. (Kanon of course doesn't need it).

And that's it! Of course this is just one possible strategy for getting your arena streak. Feel free to share yours in the comments.