Dragonknight

This is a 10th level spell.            Casters: 3

This spell summons an adult dragon of any species that you wish that is CR 16 or lower that remains for the duration. It appears at a point within range and acts immediately before you in the initiative count. When the dragon is summoned, if you were standing within 15 feet of the point at which the dragon was summoned, you bound yourself to the power of the dragon, granting you the following effects that last for the next 15 minutes. You gain resistance to the damage type (or one of the damage types) dealt by the dragon's breath weapon, you have advantage on saving throws against the abilities and breath weapons of creatures of the dragon type, and whenever you make an attack that deals damage you can have the attack deal an additional 1d6 damage of the damage type you have resistance you have. When the dragon is summoned, it attacks your opponents to the best of its abilities (on the first round, it prefers to breathe fire on an enemy, if possible). You can direct the dragon not to attack, to attack particular enemies, or to perform other actions.

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).