A team consists of 5 heroes of your choosing, along with the troop that you choose to send it into battle with. Although you may purchase extra team slots, this is generally not recommended because the 5 total teams that you are given upon account creation is overwhelmingly considered sufficient.
The game begins with a tutorial lead team composed of Lianna, Commander Grey and Colen. Despite victory in the first battle through the use of Grey's special skill, Thunder Ultimatum, they are defeated in the second. Grey is captured and the team is disbanded only to be replaced by a 1* team composed of Derric, Brand, and Tudan. Layla then joins via a daily summons and Bane joins via an epic hero summon. Sharan becomes the first hero to graduate from the base's newly built Training Camp and, with the powerful Bane remaining on the right flank, Sharan replaces Tudan in the central position in the lineup.
Changing Your Team
To change which heroes you have in your team you go to the Heroes button at the bottom of the screen. On the bottom right of the Heroes screen is the button "Edit Team". Once there, you may swipe to the right or left to access the different teams that you have available, 1 through 5. After you find the team that you would like to edit, tap on the slot (which is the order that they will appear on the field) and then tap on the hero that you would like to take that slot.
It should be noted that while Team Cost is very relevant to teams in general, in its current form it's an antiquated feature that does not have an impact upon any team in practice. At Player Level 10 you may field a full squad of fully ascended 4* heroes, and at Player Level 30 you may field a fully ascended squad of 5*.
You may also rename each of your teams simply by tapping on its name.
Defensive Team Composition
A quality team should work together to produce something that no hero would be capable of on their own. Imagine if you will, a team of 5 single-target DPS (damage per second?), each doing their full 100% damage. This would give you 500% damage total, if you add all the heroes together. Trading out just one of those snipers for a damage buffer that increases damage output by 30% would provide 400%+(400*0.3), or 520%. A good team will work together to make all members of the team stronger.
The hub of a team is its tank. Kashhrek and Guinevere are two iconic tanks. This is not just because they both have high defense and health, but they also have an ability that when triggered changes battlefield conditions to your favor. Kashhrek has a powerful heal & buff that hits himself and splashes to either side, while Guin heals her team and reduces enemy mana. It is this dual-threat that can also absorb multiple hits that makes heroes excel in the tank role.
Along with the tank, one (and sometimes two) healers is generally preferred on any given team. Since the healer needs mana to be effective, they are usually placed at the flank of the tank. On the far edges are usually the single-target damage dealers, those who could potentially finish off part of the enemy team solo. Ideally these should also be Fast Mana Heroes.
All told, a tank, a healer, a damage dealer (or two), along with a buffer and/or debuffer generally makes a quality team. Do note that most buffs are not additive, so if you have one Attack +30% and another Attack +30% all that you did was reset the duration of the buff with the second casting. As such, it is recommended that each hero effect distinct buffs/debuffs. All of this must be achieved with your opponent in mind in order to counteract their composition well. Color stacking is a common way to do this.
Taking down a particularly formidable tank (like Kashhrek or Guinevere mentioned above) may require that you double up on a particular element in order to take them down effectively.
Common approaches to Color Stacking:
- 3x2: 3 the strong element against the enemy's tank, 2 of the strong element against their second greatest threat.
- 4x1: The off-color is your healer, the 4 are your strongest element or that best counter their tank.
- Mono: all the same color.
Color Stacking has both an upside and a downside: the downside is that you are at the mercy of the board and may not get the tiles that you need to do damage and gain mana, effectively losing the battle before it even begins. The upside, however, is pretty great when it works out: any damaging tiles do the damage of multiple heroes when they strike a target and all heroes mana up at the same time. Because of the inconsistency of playing mono and 4x1, 3x2 is the most common form of Color Stacking.
For a more in depth discussion on the merits of the various ways and reasons to stack colors, see this thread on the forums.
Team Composition Calculator
With all of this in mind, there is a Team Composition Calculator created by Razor that may be of interest if you are wondering which of two or three heroes deserves to be in a particular spot within your team, or to determine which hero needs upgrading most desperately. Calculator only includes 3-5 star heroes.
Razor also puts together a Weekly Review of the most commonly used heroes by the top 100 raiders.