The One

This spell can only be casted when the sun shines on the caster. Casting this spell in absence of the sun causes the caster to receives 2d20 fire damage and this spell fails to activate. This spell can also be casted only once every long rest. Attempting to cast this spell again before taking a long rest results in a d20 fire damage to the caster. 

Upon successfully casting this spell, you become for one hour the manifestation of invincibility: as your muscular mass (+175lbs) and height (+3ft) increase, your body increases its temperature to the point that you get surrounded by flames. With these physical changes, you gain a Constitution (+7), Strength (+6), and Dexterity (+5) bonus. Furthermore, you become immune to any magic attack for 1 turn and any physical or magic strike by you delivered within the first turn is an assured critical hit, upon successful hit, until the spell ends.

Because of the immense heat your body produces after casting this spell, nearby ally and enemy creatures within 10ft of you need to succeed on a Constitution saving throw or receive a 1d6 fire damage. Ally and enemy creatures within 5ft of you need to succeed on a Dexterity saving throw instead, or receive 2d6 fire damage. These effects occur every turn until the spell ends.

Finally, after casting this spell, if the caster is holding in one hand at least one weapon having the Versatile and/or Reach properties, the weapon becomes imbued of fire for the entire duration of this spell, dealing an additional d6 fire damage everytime it is used for an attack if and only if the caster has full HP. Upon taking damage, any weapon effect given by this spell is nullified and the flames surrounding the weapon only cast a warm light that spreads 3ft radially.

*This spell can only be casted once a day, and only after a long rest.

*This spell cannot be dispelled for one turn after casting it.

*If this spell is casted outside fighting scenarios, it ends after 1 hour from successfully casting it.