Mage Hunter

You have spent a great deal of time researching magic, and magic users in general, learning all the skills necessary to turn powerful casters into nothing more than prey for you.

Arcane Quarry

You have spent a large part of your life studying magic, finding the best ways to fell those who wield it against you; at 3rd level, you gain a number of benefits based on your research:

• You gain expertise in Intelligence (Arcana) checks
• You can utilize any spell scrolls, using your Intelligence instead of the set DC or modifier
• You can cast Detect Magic as a ritual
• When in combat against a spellcaster, you can use your bonus action to make an Intelligence (Arcana) check against their spell saving throw DC. If you succeed the check, you no longer need advantage on an attack roll to deal sneak attack damage to them

Deflect Magic

Starting at 3rd level, you can use send any magic-based projectiles back at their caster to devastating effect. If you are targeted by a magic-based attack roll or damaging aoe effect is centered on you, you can you use your reaction to change the target of the attack or center the aoe on the caster instead. After you use this reaction, you must recharge it on a roll of 5 or 6, with it automatically recharging after combat ends.

Pilfer Magic

Starting at 9th level, you gain the ability to absorb magic from a defeated spellcaster; once per long rest, if you spend 10 minutes concentrating on a ritual, you can drain the magic from an unconscious or dead spellcaster, killing them if they were unconscious. After the ritual is complete, you gain all of the spells they had prepared, up to your proficiency bonus in level. You can cast their cantrips at will, and can cast all of their leveled spells once, using your own Intelligence and Proficiency Bonus. After your next long rest, the magic fizzles out and you lose access to the spells.

Sealing Strike

At 13th level, your strikes can temporary sever a caster's connection to their magic. Once per round, when you deal sneak attack damage to a spellcaster, you can force them to make a Constitution Saving Throw against your Spell Save DC, losing the ability to cast and concentrate on spells for one minute on a failure. They can repeat the saving throw at the end of their turn. Additionally, at 13th level, you recharge Deflect Magic on a roll of 3 or higher. 

Finders Keepers

At 17th level, when you use your Pilfer Magic feature, you can choose to permanently keep one leveled spell. You can keep up to half your proficiency bonus (rounded up) in spells, and can cast them each twice (level 5-6), three times (level 3-4), or four times (1-2) per long rest.