"Those who neglect to sharpen their mind might be no better than animals. But having a helpless body unable to enact change in the world might be even worse."
This subclass is about turning the Mage into a capable melee combatant.
Level 3
Martial Studies.
You can wear Leather and Mail Armor and have Advantage on Concentration checks.
Arcane Ward.
(INT/encounter) Spell you use to Defend cost -1 mana.
Savant's Strike.
(1/round) After attacking in melee you can cast a cantrip for free.
Level 7
Watchful Guardian.
Spells that allow you to Defend for free as a Reaction may be casted on a Single Target at Range 4 using your Defense Reaction.
Mage Armor.
Gain INT Armor.
Level 11
Eldritch Knight.
You can wear Plate Armor, use all Melee Weapons and all Shields.
Magical Bulwark.
If you Defend using a spell you can perform a second Defend Reaction this round.
Level 15
Instinctual Defense.
When you Defend using a spell, if you took no damage, you gain an additional Action for your next turn.