Below you will see a guide made by Glum on how to never lose in the Arena of the game Brave Frontier on iOs and android devices.
To start, here is the team I currently use. I haven't lost since using these guides, and I've never ever missed a turn 2 BB.
Zurg (breaker) - Lexidia to boost his HP
Maxwell (lord) - Amano and Sol Generator
Kuda (breaker) - Hween sphere and Sol Generator
Ardin (breaker) - Amano
Hogar (breaker) - Amano
Step 1: Pick Your Units
BB Types:
In general, picking units with an AOE BB is the best option. There are three major types of AOE BB:
15 BC requirement, does 190% damage at max BB10. (Lira, Farlon, Uda, Hogar, etc)
28 BC requirement, does 240% damage at max BB10. (tons of units fit this category)
34 BC requirement, does 250% damage at max BB10 and typically has a status effect. (tons of units fit this category)
A good arena team always has at least 4 units that can activate an AOE BB. In general, you don't want to have only the 15-BC requirement units because they alone generally can't wipe out a team. (One or two of these units is okay, but you don't want to place your chips in such weak-damaging units.) The 240% damage units generally can kill the whole team alone. These are the ones you should focus on.
Dropchecks:
Arena is all about high dropcheck. (Note: This doesn't mean high hitcount.) To find a unit's dropcheck, go here: http://touchandswipe.github.io/bravefrontier/comparemaxbc#_=_
Typically, you want your team to have at least 180 dropchecks to maintain a turn-2 BB (without Ares/Zelnite) and 120 dropchecks (with Ares/Zelnite). Note that a Lexida Sphere or a Halloween Sphere does double your unit's dropchecks.
Here are the units with 24 or more dropchecks. I've marked the top-tier units with green. They are all okay to use, but try to make sure you have at least 4 units with AOE bb's.
- Len (50 dropchecks but random BB and he's got low stats)
- Melchio (39 dropchecks but his BB is useless)
- Lucina (36 dropchecks but her BB is only single-target)
- Deemo (34 dropchecks but she's weak)
- Rickel (32 dropchecks, but she's only single-target)
- Serin (32 dropchecks, but she's weak)
- Narza (32 dropchecks, but his BB is useless)
- Grybe (30 dropchecks, AOE BB)
- Michele (30 dropchecks, strong utility on her BB if she's first to attack)
- Duel-SGX (30 dropchecks, decent utility on his BB if he's first to attack)
- Elza (30 dropchecks, hella-strong BB)
- Kuda (30 dropchecks, probably best unit in the arena)
- Heidt's 6* (30 dropchecks but single-target BB)
- Eve (28 dropchecks, strong AOE BB)
- Cayenna (28 dropchecks, weak unit)
- Alyut (27 dropchecks, strong BB)
- Logan (27 dropchecks, rainbow lead, single-target BB)
- Zelnite (26 dropchecks, very strong BB/fills other unit's BBs if casted)
- Faris (26 dropchecks, single-target BB)
- Shida (26 dropchecks, strong AOE BB)
- Kikuri (24 dropchecks, strong BB)
- Ardin (24 dropchecks, strong AOE BB)
- Farlon (24 dropchecks, only needs 15 BC for his BB)
- Sodis (24 dropchecks, strong BB)
- Bran (24 dropchecks, rainbow leaderskill, AOE BB)
- Agni (24 dropchecks, single-target)
- Yujeh (24 dropchecks, AOE BB but bad stat distribution for arena)
Step 2: Pick Your Leader
In arena, your first priority is to ensure that all 5 of your units get their BB gauge full. This is extremely easy to do with so many high-class units these days.
Option 1: ATK (Zurg, rainbow leads, mono-element leads, Azael)
Most good teams nowadays can get full BB gauges without the need of a BB fill leader. This means taking a 50% ATK leader makes your team so much more deadly. The team I run can get 3 kills on turn #1 almost every game.
Zurg is obviously the best leader currently because you get 100% ATK on the first turn. Most squads running Zurg lead can wipe out 2-5 of the enemy units by the first turn.
Option 2: BB Filling (Uda, Elza, Zelnite, Kuda, or Phee)
Take these if you are having a hard time filling all 5 units' BBs. Filling the gauges is a priority, so if you can't, make sure you run Zelnite, Uda, or someone similar.
Step 3: Choose the Order of Attacking
(thanks to http://www.reddit.com/r/bravefrontier/comments/2ksl5k/team_building_arena/ for the info here)
This is probably the most important part of arena in ensuring a guaranteed win. Every unit has a specific type of programmed AI that tells them when to activate their BB. If you end up in a turn with all 5 units not using their BB, you probably put them in the wrong order.
To see what type of AI your unit is, look it up on http://touchandswipe.github.io/bravefrontier/skillseffectsguideglobal#_=_.
Type 1: 2nd best type
60% purely random chance to cast BB
If they don't cast BB, 30% chance of attacking the unit with highest ATK
This type can go anywhere in the squad. I like to place them after the type 2's
Type 2: worst type!
60% chance to cast BB if one or more enemies is above half-HP
If not, a purely random 20% chance to cast BB
This type should always go first. If they are not the first unit, they will probably not cast their BB.
Type 3: best type
60% purely random chance to cast BB
If not, 20% random chance to cast BB on the target with highest ATK
If not, 30% chance to atk enemy with lowest HP
This type can go anywhere. They are the best type because they have a 68% chance of casting BB.
Type 4: 2nd-worst type
60% chance to cast BB if if at least one enemy is below half HP
If not, 30% random chance to cast BB
If not, 70% chance to atk enemy with highest HP
If not, 30% chance to atk enemy with lowest HP
This type should always go last in the order because chances are the last-attacking unit will probably have half-HP.
A good squad is going to emphasize the random chance of BB without any stipulations. You don't want to have a full team of types 2 and 4 because they have strict restrictions on casting a BB. Having one of each isn't bad, but you want your best arena squad to have at least three units from types 1 or 3.
There is a lot of analysis that can go in here for plays and counterplays, but in general as long as you don't have lots of units from types 2 and 4, you are basically guaranteeing a BB. Also, making sure that Type 2 is first and Type 4 is last will help a lot with ensuring BB's.
Step 4: Spheres
There are only two types of spheres you should try to use in the arena:
Halloween & Lexida. These spheres are OP for the arena. They double your hitcount and they increase your damage by about x1.7. They are statistically the best for a turn-1 kill and for a turn-2 BB. You should always use all 3 of these in an arena team.
Amanohabaken. These spheres are also very strong. A 75% increase to ATK and a 5% increased crit chance helps guarantee a lot of damage on the first turn. They also add a lot of punch to a turn-2 BB, helping ensure that practically any unit's BB will guarantee a win.
For secondary spheres, I wouldn't focus on Sphere Frogging a unit that you only use in arena. However, many units like Maxwell, Elza, Kuda, and Zelnite are excellent candidates for sphere frogs. They should basically get these items:
Sol Generators. These are only good as secondary spheres if you can't guarantee a turn-2 BB.
Havoc Axe/Geldnite Axe. These can help ensure 3 kills on the first turn. However, Sol Generators have priority if you need the extra BC generation.