Wondrous Item

Legendary Requires Attunement

You gain a +1 bonus to spell attack rolls. You also gain the ability to cast one of your 1st level warlock spells without expending a spell slot. Once you have cast a spell in this way, you can't do so again until you finish a long rest.  

Awakened

When a character awakens this item, apply the following changes to the item's traits.

You gain a +2 bonus to spell attack rolls.

You score a critical hit with spell attack rolls on a d20 roll of 19 or 20.

The level of spell you can cast without expending a spell slot increases to 3rd level. If the spell is lower than 3rd level, it is cast at 3rd level.

Exalted

When a character exalts this item, apply the following changes to the item's traits.

You gain a +3 bonus to spell attack rolls.

When you cast a warlock spell, you can grant yourself advantage on any attack rolls for the spell. You can use this ability twice per long rest. Additionally, you can instead expend a use of this ability when you cast a spell that requires a saving throw to force the target(s) to roll with disadvantage.