Hello everyone and welcome to my 223rd analysis, this time featuring Mephisto.
Overview: As of writing, Mephisto is one of the two only monsters who have Mega Taunt as their SC, the other being Dunn Ra. Because of this, Mephisto automatically finds itself at the center of the metagame, and he performs excellently there. Mephisto doesn't just sit there taking attacks like old tanks such as Ouros did, as this monster has excellent Stamina Draining skills along with Tortures. What's more, Mephisto has a move that gives him Mega Taunt along with Legendaryphobic Shield, meaning only moves with the special element will damage him. His SC is also notable for absorbing enemy SCs like Draghar's Sunburn or Wangzhou's Stamina Drain. However, Mephisto will find itself a bit too passive sometimes, as his best moves don't do direct damage to enemies, plus buff/debuff control will ruin him.

-You Shall Not Pass
-Hellfire Bite
-Through The Circles
-Sit And Intimidate
Runes: 3 Life
Mutant Rune options: Life&Speed
Relics: Armors and Swords

Build Explanation:
You Shall Not Pass refreshes Mephisto's Mega Taunt in the event that it gets removed, and it gives him a Legendaryphobic Shield that blocks all elements except special. Hellfire Bite Burns and Ignites all enemies while giving Mephisto an extra turn, which makes it an excellent Torture tool. Through The Circles drains 100% Stamina from the target, which is always a useful effect. Lastly, Sit And Intimidate removes 50% Stamina from all enemies and gives them Nightmares, making it useful for nailing enemies after they recharge - plus the Nightmares it gives is important for the Relics.
3 Life with Speed Mutations is the standard for Tanks that have (Mega) Taunt SCs or Taunt as their trait, but you can replace 1 Life with a Team Speed Rune to up your team's Speed a bit.

Teammate Options: Mephisto will fit in any team thanks to his SC, but you can increase synergy by using other Stamina Drainers with him. Wangzhou in particular makes for a fantastic ally thanks to his SC that drains 50% Stamina from all allies, which allows Sit and Intimidate to drop all enemies' Stamina to 0. From there, Wangzhou's Stamina Drain antics will probably keep the enemy occupied for the rest of the battle, allowing your other teammate, who's hopefully an attacker, to finish the job. Tortures other than Ignite and Burn will rack up serious damage, like Wyrmlad's Curse and Sunburn. Warmaster Elvira can give her team Evasion, which will be kept intact even if an AOE buff removal is used, thanks to Mega Taunt absorbing all instances of it. For more Teammate options, check out this article.

Countering Mephisto: Buff removal is essential in dealing with Mephisto, as it's nearly impossible for you to win if you wait both of his Mega Taunts to wear off. Try to use single target buff removal since it will have the same effect as an AOE. It's very likely that you'll be left in a spot where you are unable to deny the enemy and they are able to deny you, and you should bring monsters with appropriate immunities to combat this. For more Counter options, check out this article.