Wave Controller

The wave controller wizard is excellent at crowd control. They are capable of creating an advantageous battlefield by concentrating on two spells at once. By concentrating on two spells at once, you effectively reduce the options of your enemies. 

Be careful, though. You burn through your spell slots very quickly!

2nd: Concentration Savant

The gold and time spent copying concentration spells into your spellbook is reduced by half. 

Additionally, while you are concentrating on only one spell, you have advantage on saving throws to maintain concentration. 

2nd: Concentration Circle

While concentrating on a spell, a sphere of runes rotates arounds you, extending 10 feet from you. These runes grant you and any creatures inside the runes half cover from ranged attacks. The ground within your runes is difficult terrain to hostile creatures.

6th: Controlled Battlefield

Your ability to manipulate the battlefield around peaks as you develop the capacity to concentrate on two spells at once. 

You suffer the following penalties while concentrating on two spells:

• Your movement speed is halved
• You have disadvantage on concentration saving throws. If you fail the save, you lose concentration on the highest level spell. Then roll a concentration save normally for the next spell
• You can only take a reaction if you choose to stop concentrating on both your spells as part of the reaction
• At the end of the first turn you are concentrating on two spells, roll a d100. If you roll a 1-10, you suffer one level of exhaustion. For each consecutive round you concentrate on 2 spells, the percentile dc increases by 5.

You can only concentrate on two spells with spell slots that are less then or equal to half your level +1, rounded down. For example, at 12th level you can concentrate on a spell cast using a 4th level spell slot and a spell cast using a 3nd level spell slot, or a 5th level spell slot and a 2nd level spell slot...etc.

10th: Buffer Zone

When you are concentrating on a spell(s), you can use a special reaction to end your concentration on all your spells. When you do so, your concentration circle extends up to 30 feet. Each creature of your choice within 30 feet must make a strength save or be pushed out of the circle. They take force damage equal to a number of d4's equal to the combined spell slots of the spell(s) on a failed save, or half as much on a successful save. For example, if you are concentrating on a 5th level spell and a 2nd level spell the creatures take 7d4 force damage on failed save.

Until the start of your next turn the runes cause ranged attacks made against creatures inside the runes to have disadvantage and half cover. The entire area is difficult terrain to hostile creatures.

14th: Overwhelm

Choose two concentration spells which spell slots add up to half your level + 1 or lower. Once per day, you can quickly dominate the battlefield all at once by placing both spells in advantageous positions.

When you do so, you use both your action and bonus action to cast those two concentration spells with the same action.

You can spend 8 hours of study to exchange one of these spells for a different one, abiding by the same slot level restrictions.