Using the colosseum (aka colo or arena) is beneficial in 2 ways
- Experience. You gain xp for both your level and your hero levels
- Gems. Once you get to 5000 or lower ranked, you gain 10 gems per 3 hours. The better you do, the more gems you get
There are many strategies, all of them revolve around hero selection against your opponent and the current constellation. Constellations are bonuses given based on certain traits of each hero. This will be shown by a star in the lower right of the character portrait. Sometimes it's worth using, other benefits are relatively minor. It's best to click the large star in the upper left to see the upcoming benefits, since it may impact your advancement patterns for your heroes.
To get better than 5000 rank, a free lineup (using the Statue) might look like:
- Fairy (Prima Donna) - Stays in back and heals your troops
- Big Tits (Tracker) - Long distance, with heavy one shot damage that can take out the fairy
- Bunny (Child of Light) - good melee fighter who has a stun attack that can immobilize multiple opponents
- Death Knight - Best at lower levels. After dying, he will come back with half life to keep fighting. Also has an area freeze attack
- Toad (Sea Squire) - This slot is based on taste. Sea Squire helps keep Bunny and Death Knight alive longer
Other options are Instead of Bunny, Vengeful Centaur or Dwarf (Soul Forger) Instead of Toad, Dream Witch (premium character who heals, but also stuns) or Demon Slayer (teleports around to take out back row defenders)
Also, note your opponents. If they are equal level, but have a better shield (i.e. purple to your blue), or a higher border color (I'll get the actual terms for them at some point), they will win. If you can't find a good matchup, click change to look for a group you can dominate.
Once past 5000, there are several various lineups, and it becomes more of a game of Rock, Paper, Scissors, Goats, Donkeys, Bananas, and Nuclear Warheads to try to match up. The most important character at higher ranks is probably Rose Knight. She gives an immediate immunity to your troops to start the battle, and those few seconds can be the difference between winning and losing when you can find opponents not using her.
The key hero most use as they move up is Fairy. As she fully heals everyone, it can be important to take her out quickly. There are various options, including not using a fairy for yourself and using 2 back row fighters such as Demon Slayer, Shade and Scarlet Bolt to pass the tanks (Bunny, Oath Keeper, Dwarf, Big Guy, etc.) and start trying to kill her and Tracker.
Finally, as you move up, always keep an eye out for Guard.2000 any time you can find one on the list. There are several theories on this, but the one that seems most logical is that when a player moves kingdoms (or is removed from the game for any reason), their slot is filled with a placeholder. This makes it possible to shoot up the rankings if you have the patience to look for them.