Arena

The Arena is the primary PvP area of the game where players may fight 1v1 other players for a rank on the server and various rewards. All heroes and units are those the player possess. It is unlocked at Player Level 15. All War Machines and Formation features are enabled in this mode, if available: Backup, Support, and Adjutants. Spell Marks are enabled.
The arena is the most reliable source of Diamonds in Era of Chaos.
=Offense=
Each player may choose to attack players with a higher or lower rank than them. The player will be able to set up an attack formation (with a hero and up to 8 units) but then the combat will happen on auto.
It makes little sense to attack players of a lower rank manually - winning the match will not increase your rank, and the battle rewards are similar. You may choose to sweep the battle though if you don't expect to be able to beat anyone of a higher rank (or if you are already ranked 1 of course).
As the attacker you always get a very strong advantage: you can adjust to your opponent's formation. You will never know the exact units, but you will be able to see their class (Offense, Defense, etc.), if they are awakened or not, and the accompanying hero. This gives you a really big advantage in abusing weaknesses in the formation - for example positioning Chargers in a way that they can attack the backline unhindered, or on contrary, placing a defensive in the face of enemy Chargers.
==Attacks per day==
Each player can freely attack up to 5 times daily.
Depending on the VIP level, the player may be able to purchase additional charges, up to 25. These charges however cost an increasing amount of diamonds.
Charges	Cost
1-2 	5
3-5 	10
6-9 	20
10-16 	40
17-19 	80
20-25 	160
==Battle Rewards==
Regardless of victory or defeat, the attacker will always get a random reward.
While in theory, the player may choose one of 3 hidden options every time, it has been strongly suggested by the community that the choice in truth makes no difference as the reward and the alternatives are generated only after the player has already chosen an option.
The three possible rewards are randomly generated out of the following pool of rewards. It is possible for the same type of reward to be generated in the same set of options, but not with the same quantity:
Quantity 	Reward
1/2/3x 	
1/2/3x 	
50/100/200 	
10K/20K/50K	
2K/3K/5K 	
1/2/3/5x 	
=Defense=
Each player can set up a defense formation dedicated to the arena. This includes a regular formation of a hero with up to 8 units, together with an associated artifact preset. Unfortunately, a particular roster configuration can not be specifically associated with the defense formation - instead, the game will automatically take the currently active roster configuration into account.
Keep in mind that the opponents attacking you will always know your formation, so try to avoid a formation they could abuse (such as an empty lane enemy chargers may sneak through for your backline).
=Ranking=
The PvP Arena follows a server ranking system where each player occupies a particular rank in the arena.
To advance, players must fight and defeat the player in a higher rank. As a result, the two players will exchange positions.
Notice that unlike other PvP such as Duel of Champions, Glory Arena, or others, the rank of each player does not reset at the end of the week, and it has no seasons. 
==Daily Rewards==
At the end of each day (at 9 PM, server time), each player is rewarded by their rank in the arena at that particular moment.
Ranks 	Total	Total	Total
1 	500 	100K 	1000
2 	430 	94K 	980
3 	380 	89K 	960
4 	340 	85K 	950
5 	300 	81K 	940
6 	270 	78K 	930
7 	240 	76K 	920
8 	225 	74K 	910
9 	215 	73.5K	900
10 	210 	73K 	880
11-20 	200 	71K 	860
21-50 	195 	68.5K	840
51-100 	190 	66.5K	820
101-200 	180 	64K 	800
201-300 	170 	61.5K	780
301-400 	160 	59K 	760
401-600 	150 	56K 	740
601-800 	140 	53K 	700
801-1000 	130 	50K 	650
1001-1500 	120 	46.5K	600
1501-2000 	110 	42.5K	550
2001-2500 	100 	38.5K	500
2501-3000 	85 	34.5K	450
3001-4000 	75 	30K 	400
4001-5000 	60 	25K 	360
5001-6000 	50 	19.5K	300
6001-8000 	30 	13.5K	240
8001-10000	20 	7000 	180
==One-Time Rank Diamond Rewards==
Each time a player advances to a particular rank for the first time on the server, they are rewarded with a one-time Diamonds reward.
For example, let's assume Timmy currently occupies Rank 55, and it is the highest Rank he has ever occupied on the server. He fights and defeats Johnny who is on Rank 45. As a consequence, he is going to receive a one-time only reward of 130 for his global progress (from Rank 55 up to Rank 45).
An hour later, Timmy finds he has been defeated and dropped down to Rank 50. He goes ahead and defeats Johnny, becoming a Rank 40. As a result, he is awarded 100 for his global progress (which is from Rank 45, which was the highest position he ever held on the server, up to Rank 40).
==Arena Rewards==
Supplementary rewards can be purchased from a special "Arena Reward" menu (see at the top of the Arena main screen).
Each reward can only be purchased once with Arena Coins. Also, each reward has a minimum current rank required. This takes into consideration the current player rank, and not that player's maximum rank in the history of the server.
Minimum Rank	Cost	Rewards
5000 	750 	200, 6
3500 	750 	4x, 4
2000 	750 	300
1000 	750 	5x
800 	830 	300K, 6
600 	830 	6x
400 	830 	50K, 4
300 	830 	8x
200 	830 	400
100 	830 	10x
50 	1000	600
20 	1000	14x
10 	1200	100K, 8
9 	1200	18x
8 	1200	600K
7 	1200	5x 15x
6 	1200	1000
5 	1500	10x, 30
4 	1500	1300, 50
3 	1500	10x, 100
2 	1500	10x, 100
1 	5000	1x, 150, 15x, 15x