You can gain additionally characters by winning them from a chest at the shop. Chests can be purchased with Crystals, Assemble Points or gold. Chest obtained with Crystals have the best chance of a hero or villain. You can also earn characters gradually by collecting Biometrics. Each character requires between 10 and 40 units of Biometrics to summon. You can view your progress in earning them by scrolling through the thumbnail portraits at the bottom of the "My Team" screen. Complete the indicated task to unlock the corresponding character. Note: Biometrics can only be found on the Elite versions of missions.
Combat types
Black Panther: Mission 8-1 "Shredding Reality"
Blade: Mission 3-4 "Mixed Up Conspiracy", Mission 5-7 "New York in Chaos #1".
Bullseye: Mission 4-3 "Mad Assassin", Mission 7-4 "Kingpin's Plans"
Doctor Octopus: Mission 3-11 "Sinister Brain", Mission 5-10 "The Last Air Strike", Mission 7-10 "Doc Ock Unleashed #3".
Hulk: Traded for Chaos Token at the shop
Iron Fist: Mission 4-5 "Power of ISO-8 #2", Mission 6-5 "Stealing the Scene #2"
Iron Man Mark 44 Hulkbuster: Dimension Chest or current event.
Kingpin: Mission 4-10 "The Beginning of the Windstorm", Mission 7-6 "Kingpin's Plans #3"
Luke Cage: Mission 2-3 "Hero for Hire", Mission 5-8 "New York in Chaos #2", Mission 6-9 "The Escape"
Punisher: Mission 2-8 "The Search for M.O.D.O.K. #2", Mission 6-6 "Stealing the Scene #3"
Venom: Mission 3-3 "Dark Street", Mission 7-8 "Doc Ock Unleashed #1"
Blast types
M.O.D.O.K.: Mission 2-9 "Mad Scientist", Mission 6-3 "HYDRA Unmasked", Mission 7-7 "M.O.D.O.K.'s True Feelings"
Malekith: Dimension Chest
Red Skull: Mission 6-10 "Red Madness", Mission 7-3 "Disharmony #3", Mission 7-11 "Reconstructed System #1"
Vision: Mission 1-5 "Another Betrayal", Mission 5-3 "Battle in the Skies #2"
War Machine: Mission 1-3 "Stolen Suit", Mission 5-5 "Battle in the Skies #4", Mission 8-7 "A Desperate Situation #2"
Speed types
Black Cat: Dimension Chest
Daredevil: Mission 4-9 "Strong Winds #2", Mission 6-4 "Stealing the Scene #1"
Elektra: Mission 4-6 "The Perfect Death", Mission 7-2 "Disharmony #2", Mission 7-5 "Kingpin's Plans #2"
Falcon: Mission 2-5 "The Darkness Beyond Dimensions #2", Mission 4-7 "Out of the Dark, Into the Light", Mission 6-2 "Back Up Plans"
Green Goblin: Mission 3-7 "In Chaos #1", Mission 7-1 "Disharmony #1", Mission 7-9 "Doc Ock Unleashed #2"
Hawkeye: Mission 4-2 "Bringing in the Big Guns #2", Mission 8-3 "Retaking the Antimatter #1"
Mockingbird: Mission 2-4 "The Darkness Beyond Dimensions #1", Mission 5-1 "A World Berserk"
Sharon Carter: Mission 3-8 "In Chaos #2", Mission 6-8 "Attacking the Core", Mission 8-6 "A Desperate Situation #1"
Spider-Man: Mission 3-6 "King Neighbors", Mission 5-9 "New York in Chaos #3", Mission 8-8 "The Showdown #1"
Winter Soldier: Mission 2-7 "The Search for M.O.D.O.K. #1", Mission 6-7 "Stealing the Scene #4", Mission 8-5 "Retaking the Antimatter #3"
Universal types
Angela: Dimension Chest
Black Bolt: Mission 8-10 "The Showdown #3"
Captain Marvel: Traded for Honor Token at the shop
Destroyer: Dimension Rift
Ghost Rider: Mission 4-4 "Power of ISO-8 #1", Mission 4-8 "Strong Winds #1", Mission 8-4 "Retaking the Antimatter #2"
Loki: Dimension Rift
Thor: Mission 8-9 "The Showdown #2"
Ultron: Mission 1-8 "Ultimate Evil", Mission 7-12 "Reconstructed System #2"
Costumes
New costumes offer more than a new cosmetic look. Each alternate uniform boosts two stats. Additionally, equipping Captain America, Iron Man and Black Widow with their Avengers: Age of Ultron costumes will change their appearances during the cinematic sequences.
Hero types
There are four different categories of heros.
Blast
Ranged snipers that work by shooting enemies from a safe distance.
Combat
Melee bruisers that use punches, kicks, or weapons in close combat.
Speed
Very fast attackers that use rapid strikes.
Universal
Balanced fighters that are not specialized in a particular style.
ISO-8
ISO-8 appears in various colors. Each color conveys different types of bonuses. Individual pieces of ISO-8 can be enhanced by sacrificing lesser ones and paying some gold. After leveling up enough, you will be able to equip multiple pieces of ISO-8. Certain color combinations will result in additional set bonuses.
Partners
Before starting a mission, you can select another player's character to assist you. A choice of three of them will appear directly below your team at the mission description screen. That character's portrait will appear on the right side of the screen. Tap it to summon him or her. You can only use your helper once per mission for a limited amount of time. Consider saving it for the Boss battle.
Ranks
Biometrics are required to promote a character to the next rank. Doing so will increase his or her level cap, as well as boost all their attributes. After collecting the required amount of Biometrics, select the "Rank Up" tab on the character's profile. You will then be prompted to spend a particular amount of gold to rank up.
Skills
Your skills are activated by buttons on the right side of the screen. Each active skill has a cooldown, with the number of seconds it will take until you can use it again displayed.
Team bonuses
At the "My Team" screen, tap the "Team Bonus" menu on the right. You can view all the different combinations of characters that will give you bonuses. The list is sorted with teams that can be made with your current characters at the top.
Upgrades
Each character has four pieces of gear that can be upgraded to increase their damage, defense, critical hit rate and other attributes. This requires gold and items that are dropped during missions. When you have the proper ingredients to complete an upgrade, a small dot will appear on the "Gear" button in a character's profile.
Skills are the easiest thing to improve, simply by spending gold. The two starting skills can be leveled at the same rate as the character's level. Always try to improve them after leveling up. Other skills will become available as you rank up that character.
You can master your heroes by using various Norn Stones. This is similar to ranking up, except the stat improvements are greater. This will also improve their leadership ability.