Mephisto

With: Cassie Lang

Synergy Champions: +6% Block Proficiency and Block Penetration for each Synergy Champion present.

With: Diablo

Diablo: Poison effects on the opponent reduce healing effects by 50% each instead of 30%. Mephisto: Gain 50% of a bar of Power when a Poison Debuff would be gained. Cooldown: 10 seconds.

With: Guillotine 2099

All Champions: +6% Attack Rating.

With: Hela

Hela: Begin the fight with 1 Bar of Power. Mephisto: Regain the first Soul spent to trigger his Soul Imprisonment each fight.

With: Hulk (Immortal)

Hulk (Immortal): At the start of each fight, Hulk sacrifices 50% his Current Health, gaining an equal amount of Gamma Radiation Mephisto: Knocking out #Villains grants +1 Soul Charge.

With: Iron Man (Infamous)

Iron Man (Infamous): Whenever Infamous Iron Man is immune to an effect, he deals the Opponent a burst of Energy Damage equal to 200% of his Attack Rating. Each subsequent time this ability triggers, the potency is reduced by 20%. Mephisto: Duration of Soul Imprisonment is doubled.

With: Kindred

Kindred: Activating Dread Aura grants an Unblockable Passive for 3 seconds. Cooldown: 20 seconds.

With: Madelyne Pryor

All Champions: +3% Attack Rating for each #Dimensional Being on the team.

With: Morningstar

Morningstar: Starts the fight with 1 Bar of Power. Mephisto: +1 Soul at the beginning of the fight.

With: Odin

Odin: For each living team member, +5% Attack Rating. Mephisto: For each knocked out teammate, +5% Attack Rating.

With: Omega Red

Omega Red: The Death Field deals 10% more damage. Mephisto: The Aura of Incineration deals 15% more damage.

With: Pixie

Pixie: +10% Attack Rating when fighting #Dimensional Beings. Other Synergy Champions: +6% Ability Power Rate.

With: Purgatory

#Dimensional Beings: Gain Bleed Immunity, 20% increased Ability Accuracy, and +900 Armor Rating.

With: Scarlet Witch

Scarlet Witch: Chaos Surge creates Regeneration instead of Prowess, granting 4% of missing health over 12 seconds. Prowess can no longer be copied, but Regeneration can. Mephisto: While the Opponent's Soul is Imprisoned, 100% chance to activate Aura of Incinerate when the Opponent fails to gain a Buff through Chance. Cooldown 1 second. Dimensional Beings: +15% increased Ability Power Rate.

With: She-Hulk

All Champions: +155 Critical Rating.

With: Silver Surfer

All Champions: +155 Critical Rating.

With: Spot

Spot: Portal Block gains a flat 10% chance to Resist Unblockable and Heavy Attacks per Spot. Mephisto: Landing Basic Attacks pauses the duration of an Aura of Incineration for 0.2 seconds.

With: Sunspot

All Champions: +125 Critical Rating. Increased to up to +325 based on Sunspot's Signature Level.

With: Symbiote Supreme

Symbiote Supreme: Special 2 effects trigger through Blocks. Mephisto: 15% Chance to trigger Aura of Incineration on Basic Attack Hits.

With: The Champion

The Champion: When The Champion has 3 or more Persistent Charges, he starts the fight with an Indestructible Buff, ignoring all incoming damage for 8 seconds. Mephisto: +15% Attack Rating for each Persistent Charge.

With: The Champion

All Champions: +155 Critical Rating.