Mephistopheles

{
  "name": "Mephistopheles",
  "page": 99,
  "__prop": "legendaryGroup",
  "source": "MaBJoV",
  "lairActions": [
    "On initiative count 20 (losing initiative ties), Mephistopheles can take one lair action to cause one of the following effects; Mephistopheles can't use the same effect two rounds in a row:",
    {
      "type": "list",
      "items": [
        "Mephistopheles casts any spell from his wizard list and if it normally requires {@status concentration}, it lasts for the full duration instead.",
        "Mephistopheles covers a 5-foot area with Hellfire. Any creature that starts their turn on that area suffers 27 ({@damage 6d8}) fire damage. The Hellfire remains until Mephistopheles dismisses it or he uses this ability again."
      ]
    }
  ],
  "regionalEffects": [
    "The region containing Mephistopheles's lair is corrupted by his presence, which creates one or more of the following effects:",
    {
      "type": "list",
      "items": [
        "Flaming winds scour the area within 2 miles of Mephistopheles's lair. Any creature with vulnerability to fire damage suffers 1 level of {@condition exhaustion} for every hour spent this close to the lair.",
        "Within 2 miles of Mephistopheles's lair, every 60 feet of movement results in a flame geyser erupting. When a geyser appears, the creature that triggered its appearance and fails a Dexterity 22 saving throw suffers 10 ({@damage 3d6}) fire damage. Damage is halved if the saving throw is successful. The geyser remains for a day."
      ]
    },
    "If Mephistopheles dies, the effects fade over the course of {@dice 1d10} days."
  ]
}