Mathias Blackflail

Mathias Blackflail was added to the game during Update 8.60. Featuring an entirely unique Champion model, the fearsome Black Knight Berserker seeks to carry out his thirst for vengeance upon Telerian soil, demanding his foes fight him face to face - only hoping never to see the eyes of hatred hidden beneath his black and gold helmet.

Designed almost entirely for Fire Knight and Phantom Shogun but with possible application elsewhere, the main draw here is the A3 "Face the Blackflail" which in turn allows for the Passive "Red Mist" to activate. Mathias' A1 "Darken the Sky" not only hits 3 times - ideal for damaging the Fire Knight's shield especially in combination with how "Face the Blackflail" supplies [Reflect Damage] to the entire team.

Against Phantom Shogun Stage 25 specifically, Mathias' Force Affinity matches up well against the boss' Magic Affinity, which alongside how both of Mathias' attacking skills heal either himself or all allies based on damage dealt would mean that there is little concern regarding Mathias' survivability during the battle. Note that Phantom Shogun applies an unblockable, unremovable and irresistable [Block Passive Skills] onto all allies, so Mathias will be unable to counterattack via the "Red Mist" Passive during the battle. Many will consider Emic Trunkheart to be the superior choice for this encounter if they acquired him during his Fusion event or otherwise obtained him from a Void Shard, due to providing [Unkillable] for the entire team.

In a way, one could suggest that it would be better if the "Red Mist" Passive was instead an unremovable [Counterattack] buff placed by A3 "Face the Blackflail" given how the [Taunt] buff in combination with [Increase RES] means that Mathias may be someone you consider as a Head of Mischief tank in the Hydra battle that also prevents your other allies being Devoured while the [Taunt] buff remains active on Mathias. Head of Mischief has higher Accuracy compared to the other Hydra heads, and even with enough RES there is the 3% chance that the [Taunt] buff alongside others are stolen anyway, unless Mathias is built in the Protection gear set, which may just prove ideal.

The A2 "Deathwhirl" is primarily going to find itself being used as a healing skill for all allies in combination with the bonus damage from the Warmaster mastery. While the extra hit can ignore 20% DEF, the relatively low damage multiplier of the skill alongside the reliance on enemies having no buffs, including ones that cannot be removed no matter what, means that it is inadvisable to build Mathias as a damage dealer in terms of CRIT and C.DMG and is instead best kept as a durable Support-style Champion despite the HP role he is given.

Ultimately, Mathias' usage for your account depends on other options available, although his lore is an interesting read about how the Arbiter cannot entirely control those that She has bound unto Shards...