The Yes Crystal is a milky white crystal shard that appears to be a small piece of a much larger whole, with jagged edges and one smooth, rounded face. It is enchanted with powerful Divination magic and is capable of manipulating probability to great extent.

The Yes Crystal can hold a maximum of 10 charges and starts fully charged. While charged, the Yes Crystal glows a fluorescent blue. That glow increases in intensity as its charge increases. As such, the Yes Crystal emits dim light with a radius of 1 foot per remaining charge, up to a maximum of 10 feet.

The attuned Wizard can, outside of combat, expend any number of Arcane Recovery charges to replenish an equal number of the Yes Crystal's charges. The attuned Wizard can, outside of combat, expend any number of the Yes Crystal's charges to replenish an equal number of Arcane Recovery charges.

Upon attunement, or upon receiving any number of additional charges, the Yes Crystal audibly requests the attuned Wizard to "Ask a 'yes or no' question," slightly above normal speaking volume. 

The attuned Wizard can ask the Yes Crystal a question as an action or bonus action, so long as the Yes Crystal has at least one charge remaining.

If the attuned Wizard asks the Yes Crystal a question that cannot be answered with a simple "yes" or "no," nothing happens. If the attuned Wizard asks a question that can be answered with a simple "yes" or "no," the Yes Crystal will shout "Yes," then attempt to use a number of charges (according to the rules defined below) to ensure that the true answer to the question is actually "yes". If the Yes Crystal is unable to do so, no charges are expended and nothing happens, although it still shouts "Yes," as usual. If the true answer to the question was already "yes," no charges are consumed.

When asked a question, the Yes Crystal abides the following rules:

• If the attuned Wizard asks a question that would result in an effect equal to a levelled spell, a number of the Yes Crystal's charges equal to the level of that spell plus one will be consumed.
• If the question would result in an effect equal to a cantrip, one of the Yes Crystal's charges will be consumed.
• Intent matters. If the attuned Wizard asks a question that would result in an effect equal to a levelled spell, the attuned Wizard can choose to increase the number of charges consumed for an equal upcast of that spell. Similarly, if the attuned Wizard asks a question that could result in an effect similar to multiple different levelled spells, the attuned Wizard can choose which effect will occur. For example, the Wizard could choose between an effect more similar to Fire Bolt or one more similar to Fireball.
• The Yes Crystal can replace an attack roll, saving throw, or ability check made by the attuned Wizard or a creature that the attuned Wizard can see, consuming a number of Yes Crystal charges equal to one third of the difference between the desired roll and the original roll, rounded up. The attuned Wizard must choose to do so before the roll, and then the roll must be made anyway. If the Yes Crystal's remaining charges are insufficient to replace the roll, no charges are consumed, and the original roll is kept. If the desired roll is equal to the original roll, no charges are consumed.
• Attacks made via the Yes Crystal always deal non-magical damage, as the Yes Crystal is not actually casting a spell but is instead manipulating probability to produce the desired effect. For the same reason, Counterspell cannot be used against the Yes Crystal.
• If the Yes Crystal is asked a question that simply cannot be truthfully answered with a "Yes", then no charges are consumed. For example, asking if someone will be struck by lightning while they are underground.
• If the Yes Crystal is asked a question outside of combat, the result of that question will take effect within three seconds of the question being asked, unless a timeframe is specified.
• If the Yes Crystal is asked a question as an action or bonus action, the result of that question will take effect at the end of the attuned Wizard's turn, unless a timeframe is specified. 
• The Yes Crystal is capable of replicating most of the effects of Wish without the relevant negative consequences. This is, of course, limited by the type of questions that can be asked by the attuned Wizard, and is limited by DM ruling.

Here's an example of a possible attack made with the Yes Crystal. If we assume the following:

1. There is a goblin in front of the attuned Wizard.
2. The attuned Wizard intends to strike the goblin with damage equivalent to Call Lightning at fifth level.
3. The goblin is outdoors.
4. The Yes Crystal has at least six charges remaining.

And the attuned Wizard asks the Yes Crystal the following question:

"Will the goblin in front of me be struck by lightning?"

This will result in the following effects, in order:

1. The Yes Crystal shouts "Yes!"
2. Six of the Yes Crystal's charges are consumed.
3. If no storm cloud is present, one appears according to the rules of Call Lightning.
4. The goblin is struck by non-magical lightning within three seconds (if asked outside of combat) or at the end of the attuned Wizard's turn (if asked as an action or bonus action), dealing non-magical lightning damage equal to Call Lightning at fifth level.

Notes: Wizard., divination