You have made a pact with a mysterious archemage of ancient times. The pact has granted you a fraction of your Patron’s knowledge, while also bolstering your spellcasting capabilities. The reason they may have given you this pact may include you gathering magical artifacts, learning secrets of the arcane, or just using you as a pawn in their schemes. Beings of this sort may include a powerful Lich, an ancient wizard, or even the momentary god Karsus.

Patron's Teachings

At 1st level, you have been granted the ability to cast spells similar your patron. When your Spellcasting feature lets you learn or replace a warlock cantrip or a warlock spell of 1st level or higher, you can choose the new spell from the wizard spell list or the warlock spell list. You must otherwise obey all the restrictions for selecting the spell, and it becomes a warlock spell for you.

Arcane Fundamentals

At 1st level, you learn two wizard cantrips, these cantrips counts as warlock cantrips, and you gain proficiency in the Arcana skill. Your proficiency bonus is doubled for any ability check you make with the Arcana skill.

Magical Resilience

Starting at 6th level, your resilience against spells and other magical effects seem to be heightened. When you have to make a saving throw against a spell or other magical effect, you can use your reaction to make that saving throw with advantage.

Once you use this feature, you can’t use it again until you finish a short or long rest.

Unrestrained Learning

Beginning at 10th level, you patron has granted you the ability to consume arcane knowledge. When you find a warlock or wizard spell of 5th level or lower, you can conduct a ritual that allows you to learn the spell. For each level of the spell, the ritual takes 4 hours and costs 100 gp. You can learn up to a number of spells this way equal to half your warlock level. Spells learned in this manner do not count towards your total spells known but count as warlock spells for you. If cannot learn additional spells and still choose to lean a new spell, you must forget one of the spells gained through this feature.

In addition, you learn two wizard spells of 5th level or lower. These spells count as a warlock spells for you, but they don’t count against the number of warlock spells you know.

Spell Absorption

Starting at 14th level, your patron has shown you the secret to absorbing the energy of spells. If a creature that you can see within 60 feet of you is casting a spell, you can use your reaction to try to absorb the spell. If the spell that was being cast is of 5th level or lower, the spell is absorbed and has no effect. If the spell is 6th level or higher, make an ability check using your spellcasting ability. The DC equals 10 + the spell's level. On a success, the spell is absorbed and has no effect. When a spell is absorbed, you can consume the energy to cast a spell of 5th level or lower without expending a spell slot. If you do not use the absorbed energy before you finish a long rest, the energy of the spell is dissipates.

Once you use this feature, you can’t use it again until you finish a long rest.