Once your party's goal had been fulfilled you're revived nature caused you to fade from this world, but after freeing him from the Ice Fang daggers, Ydriss the White Dragon forms a pact with you to prolong your life, as he feels that you may still be of use in this world

Expanded Spell List

Ydriss lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

1. Ice Knife and Chromatic orb
2. Dragons Breath Snilloc's Snowball Swarm
3.  Elemental weapon and Fear
4.  Ice Storm and Fire Shield
5.  Cone of Cold and Control winds

 

Vessel of Ydriss

When you take this pact at 1st level, Ydriss' spirit manifests as a pale white Pseudodragon familiar with the statistics of a pseudodragon. You may use it's senses as long as you are within of 100 feet, and may cast spells that require touch through it. The Pseudodragon disappears if you or it dies, and can only take the dash, disengage, or hide in combat. At the end of a rest, Ydriss' spirit reforms into the familiar. Also, while it is perched on your shoulder you can speak and read draconic.

Influence of Ydriss

Starting at 1st level,  when you cast Eldritch Blast, it does cold damage instead of force. Additionally,  when you hit a target with a melee attack, you may choose to deal cold damage equal to your Charisma Modifier, you may only apply this bonus damage once per short or long rest

Wings of Ydriss

Starting at 6th level, as a bonus action you can choose to sprout illusory wings and gain a flying speed equal to your current speed for 1 minute, or you cloak yourself with illusory wings to vanish into a cloud of snow and reappear in a space up to 30 feet that you can see. Once used, you cannot use this feature again until you have finished a short or long rest.

Scales of Ydriss

Starting at 10th level, you gain immunity to being frightened, and resistance to cold damage.

Additionally, When hit by an attack, you may use your reaction to retaliate. Once per long rest you may reflect the damage as cold damage, otherwise you attempt to slow the attacker. They must make a Constitution saving throw against your warlock spell save DC, on a failed save, They have their speed reduced by half feet until the end of their next turn  

Form of Ydriss

Starting at 14th level, as an action, you may imbue yourself with the might of Ydriss for 30 seconds

• You sprout dragon wings and gain flying speed of 45 feet
• You become partially coated in white scales, increasing your AC by an amount equal to your Charisma modifier(minimum of 1)
• You use the freezing power of Ydriss to add 2d10 cold damage to a melee attack once per turn (this cannot be used alongside the damage bonus from Influence of Ydriss)
• As an action, you may use the powerful presence of a dragon to frighten your enemies. Each enemy within a 15 foot radius of you must make a Wisdom save against your warlock spell DC, on a failed save, they are frightened of you until the end of your next turn

You may only use this feature once per long rest