Bogardan Hellbringer

This is a 11th level spell.          Casters: 7

You channel dark draconic fire magic through yourself and your components, causing you to summon an ancient black dragon with 355 hit points, immunity to fire damage instead of immunity to acid damage, breath weapon deals fire damage instead of acid damage, and no proficiency in Persuasion or Deception, at a point within range.  When the dragon is summoned, it immediately makes a Breath Weapon attack while targeting all hostile creatures within range, which does not count as the dragon's action for that turn. While using its breath weapon in this way, the DC to succeed on the Constitution save increases to 24 and the fire damage dealt on a failed save is 19d6 instead of 22d6, or half as much on a success.

The dragon then remains for the duration, being friendly to you and hostile to everything else. The dragon does whatever it wants, which may include attacking your allies and such, though you can attempt to calm it to obey one of your spoken commands with a successful DC 19 Charisma check.

In ancient time of the world of D&D there were no limits for what magic could do. But then Mystra, the goddess of magic, after having to kill herself to save the weave from Karsus' foolishness, decided that such magic was too powerful, reducing the strength of spells an individual could cast to 9th level. Due to the impossibility for a mortal to have 10th level or higher spell slots, there must be a number of secondary casters, each using a 9th level spell slot, to cast it as shown in the Casters. In addition to the secondary casters there are also the main caster who is the person actually casting the spell. This person chooses the targets of the spell and any other choice that must be made to cast the spell and could actually make a spell target some of the secondary casters even if they did not agree to. If a spell requires concentration its only the primary caster who must maintain concentration. Immediately after casting a 10th level or higher spell, all casters must make a DC (9+spell level) Constitution save or suffer from 1 level of exhaustion (10th or 11th level spell), 2 levels of exhaustion (12th or 13th level spell), 3 levels of exhaustion (14th or 15th level spell), 4 levels of exhaustion (16th level spell), instant death (17th level or higher spell).