Defender

Requires Attunement
You gain a +3 bonus to attack and damage rolls made with this magic weapon.
The first time you attack with the sword on each
of your turns, you can transfer some or all of the sword's bonus to your Armor Class, instead of using the bonus on any attacks that turn. The adjusted bonuses remain in effect til the start of your next turn, although you must hold the sword to gain a bonus to AC from it.