Teyo, Aegis Adept is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

+1: Up to one target creature's base power perpetually becomes equal to its toughness. It perpetually gains "This creature can attack as though it didn't have defender." −2: Conjure a card named Lumbering Lightshield onto the battlefield. −6: You get an emblem with "At the beginning of your end step, return target white creature card from your graveyard to the battlefield. You gain life equal to its toughness."

Complete guide

Teyo, Aegis Adept is a powerful white planeswalker designed for Alchemy and Historic play, focusing on defensive synergy and perpetual modifications. By shifting how creatures calculate damage and conjuring reinforcements, Teyo serves as both a shield and a persistent engine for graveyard recursion.

Perpetual Fortification

Teyo's first ability utilizes the digital-only 'perpetual' mechanic, meaning the change lasts for the duration of the game, even if the creature moves to the graveyard, hand, or library. It transforms a creature's base power to match its toughness and allows it to ignore the restrictions of defender. This makes high-toughness walls formidable attackers that don't lose their potency when blinking or changing zones.

Conjuring the Lightshield

The second loyalty ability conjures a Lumbering Lightshield directly to the battlefield. Because the card is conjured, it acts as a real card for the rest of the game rather than a token. When it enters, it taxes an opponent's resources by randomly increasing the mana cost of a nonland card in their hand perpetually, providing disruptive pressure alongside a 1/4 body.

The Ultimate Engine

Reaching Teyo's -6 ability grants a permanent emblem that triggers every end step. This creates a loop of value, returning white creatures from your graveyard to the battlefield and granting you a life buffer. Because the life gain is tied to the creature's toughness, this scales perfectly with creatures you have previously buffed using Teyo's first ability.

Interaction examples

Shielding the Frontline

Lumbering Lightshield

You activate Teyo's -2 ability to conjure a Lumbering Lightshield. On your next turn, you use Teyo's +1 ability targeting the Lightshield. Its base power perpetually becomes 4 (matching its toughness) and it gains the ability to attack despite having no native defender keyword. You now have a 4/4 attacker that previously taxed your opponent's hand.

High-Value Resurrection

Lumbering Lightshield

With Teyo's emblem active, your Lumbering Lightshield dies in combat. At the beginning of your end step, the emblem triggers, returning the Lightshield to the battlefield. You gain 4 life because its toughness is 4, and its enters-the-battlefield ability triggers again, perpetually increasing the cost of another card in your opponent's hand.

Guide written with AI from the official text and rulings. Official English text prevails.